The Effects of Feeding Enrichment on Behavioral Measures of Welfare in Four Bear Species

Home , Acinonyx, Maned wolf, Spectacled bear, Stereotypy (non-human), Sun bear

THE EFFECTS OF FEEDING ENRICHMENT ON BEHAVIORAL MEASURES OF WELFARE IN FOUR BEAR SPECIES

JASON DANIEL WAGMAN

Submitted in partial fulfillment of the requirements for the degree of Master of Science

Department of Biology CASE WESTERN RESERVE UNIVERSITY

August, 2015 CASE WESTERN RESERVE UNIVERSITY

SCHOOL OF GRADUATE STUDIES

We hereby approve the thesis of

______Jason Wagman______candidate for the degree of ______Master of Science______.

______Mandi Wilder Schook, PhD______(chair of the committee)

______Kristen E. Lukas, PhD______

______Pam Dennis, DVM, PhD______

______Mark Willis, PhD______

______March 19, 2015______

*We also certify that written approval has been obtained for any proprietary material contained therein.

To my parents, for loving me like only parents can, for always taking me to zoos, for instilling in me a passion for wildlife, and for some wonderful times in wild places.

To my wife. For saying yes at a crazy time in our lives, and for giving so much love during some of the most difficult times in our lives.

I couldn’t have done it without you.

Table of Contents

List of Tables ……………………………………………………………………………. iii List of Figures ………………………………………………………………………….... iv Acknowledgements………………………………………………………………………..v List of Abbreviations …………………………………………………………………… vii Abstract ………………………………………………………………………………... viii Introduction …………………………………………………………………………….... 1 1. Animal Welfare ……………………………………………………………..… 1 1.1 Definition of Welfare ………………………………………………... 1 1.2 Animal Welfare in Zoos….…………………………………..……….. 2 1.3 Behavioral Evaluations of Animal Welfare ...…………………….….. 3 1.4 Using Behavioral Data to Inform and Assess Improvements in Animal Welfare …………………………………………………………...…...6 2. Bear Biology and Behavior ……..…………………………………………….. 7 2.1 Behavior in the Wild ………...…………………………………….… 7 2.2 Behavior in Zoos ….………………………………...……....……..... 10 2.3Effects of the Environment on Behavior and Welfare ……...………... 17 3. Promoting Positive Affective States ...……….………………………………. 18 3.1 The Use of Enrichment in Zoos ..…………………………………… 20 3.2 Effects of Enrichment on Behavior and Welfare ..………..…………. 22 Study: Using Behavioral Measures to Assess the Effects of Feeding Enrichment on the Welfare of Four Bear Species 1. Introduction ………………………………………………………………….. 30 2. Methods ……………………………………………………………………… 34 2.1 Animals and Animal Care.…………………………………………... 34 2.2 Study Design……………………………..………………………….. 35 2.3 Behavioral Data Collection ………………………………………..... 40 2.4 Statistical Analysis …………………………………………….……. 42 3. Results ……………………………………………………………………….. 45 3.1 Experiment One ………………………………………………….…. 45 3.2 Experiment Two ……………………………………………………. 51 4. Discussion …………………………………………………………………..... 56 5. Conclusions……………………………………………………………………64 Works Cited …………………………………………………………………………….. 67

List of Tables

Table 1: Ethogram used for behavioral data collection ………………………………... 41

iii

List of Figures

Figure 1: Timeline for experimental design..…………………………………………… 38

Figure 2: Example enrichment and observation schedule with photos of all enrichment items used in the study…………….…………………...……………………………….. 39

Figure 3:Differences in exploratory behavior between the experimental periods in Experiment One, paneled by observation time ..….…..………..…………………….… 48

Figure 4:Differences in abnormal behavior, self-directed behavior, and visibility between the experimental periods in Experiment One ...……...………………………..……...… 50

Figure 5:Differences in exploratory, abnormal and stationary/rest behaviors between the experimental periods in Experiment Two, paneled by observation time …...... ……...… 54

Figure 6:Differences in Shannon-Weiner diversity indices between the experimental periods in Experiment Two ……………....………….………………………..……...... 55

Acknowledgements

Many people have given me the support necessary for me to achieve the completion of this degree. I would like to first thank my advisor, Mandi Schook. She has offered more hours, thought, advice, and passion than I could ever have expected or hoped. Whether it was early morning e-mails, late night phone calls, frequent office visits or weekend-long flurries of revisions, she has been there for me every step of this journey, doing her best to ensure my academic, career and personal success. Mandi, I could not have done this without you. Thank you.

I’d like to thank the rest of my committee. Kristen Lukas, Pam Dennis, and Mark

Willis gave invaluable advice at all stages of this research project. Thank you Kristen for making this program a great success, for being our go-to expert on all things animal behavior, and for your emotional support during some very tough times. Thank you Pam for your million ideas per minute, for always being open to answering questions, and for always being willing to ask the tough questions. Thank you Mark for helping me navigate the academic world, for always being a source of guidance and humor, and for bringing a fresh perspective to the zoo world.

There are a number of other people I have to thank at Cleveland Metroparks Zoo.

I would like to thank the other team members in Conservation & Science. Thank you

Jason Wark, Austin Leeds, Bonnie Baird and Laura Amendolagine for your friendship, advice, and empathy over the past several years, and for allowing me to vent when the pressure was more than I could take. Thank you Kym Gopp for allowing me to pursue my interest in conservation, for your emotional support, and for helping me develop a new set of skills. I would also like to thank Travis Vineyard for being the inspiration behind this project and for his support of this research project and Michael Murray for his

v daily support and for helping me with the logistics that allowed this project to succeed.

Thank you to the keeper staff in Northern Trek, Joe Carroscia, Curt Gindlesperger, Mark

Chase, Patty Young, and Aimee Kindry, for your assistance in constructing and implementing the enrichment items used in this project and for accommodating my research in conditions that were often less than ideal. Thank you to my volunteers for the many hours you put into behavioral observations and data entry in often inclement weather.

Finally, I would like to thank my parents, Cindy and Daniel Wagman for instilling in me the compassion, work ethic and integrity essential to my success. Thank you to my sister and brother-in-law Amy and Phillip Gillette for being models of academic excellence, for many hours of proof reading, and for the love and advice that has helped get me to this point. My wife, Nadia Wagman, deserves much more than my thanks. I love you for being a constant partner on a sometimes very emotional journey, for helping me find a work-life balance, for holding me accountable, for mourning with me and celebrating with me, for helping me relax when necessary, for being the pressure to keep me moving forward when necessary, and for being a source of so much joy in our lives.

List of Abbreviations

AZA – Association of Zoos and Aquariums

GLMM - generalized linear mixed models

T1 – early morning observation (1000-1130)

T2 – late morning observation (1130-1300)

T3 – early afternoon observation (1330-1500)

T4 – late afternoon observation (1500-1630)

USDA – United States Department of Agriculture

WAZA – World Association of Zoos and Aquariums

vii

The Effects of Feeding Enrichment on Behavioral Measures of Animal Welfare in Four Bear Species

Abstract

JASON DANIEL WAGMAN

Zoo-housed bears are prone to exhibiting stereotypic behaviors, which are generally considered indicators of negative welfare and often addressed with environmental enrichment. This study examined the effects of feeding enrichment on behavioral time budgets and normal behavioral diversity in four bear species at Cleveland

Metroparks Zoo. Because there have been no systematic efforts to examine the effects of an unpredictable feeding schedule in bears, the aim of Experiment One was to test the effects of fixed- vs. variable-time presentation of “work-for-food” enrichment.

Experiment Two aimed to determine if habituation to enrichment occurred over a 30-day period when using a semi-variable schedule. Feeding enrichment was associated with increased exploratory behavior and decreased abnormal behavior in both experiments; adding unpredictability to the feeding schedule increased the magnitude and distribution of exploratory behavior compared to a fixed-time schedule. No habituation was observed during the 30-day sustained enrichment period for these behaviors.

viii Introduction

1. Animal Welfare

1.1 Definition of Welfare

Modern zoos seek to continually improve the standards of animal care in zoos and

aquariums (hereafter referred to as zoos) and the quality of life for individual animals

within the context of animal welfare (e.g., Barber, 2009; Goulart et al., 2009; Hill and

Broom, 2009; Swaisgood, 2007; Watters, 2014; Whitham and Wielebnowski, 2013).

Welfare can be defined as “an individual’s state as regards to its attempt to cope with its environment” (Broom, 1986) and is typically rated on a scale from poor to good (Hill and

Broom, 2009).

Animal welfare assessments have historically focused on negative welfare and paid little attention to promoting positive welfare. For example, in 1992, the five freedoms were the main principles by which animal welfare was judged [freedom from hunger and thirst, freedom from discomfort, freedom from pain, injury and disease, freedom from fear and distress, and the freedom to express natural behaviors (Farm

Animal Welfare Council, 1992)]. There has also existed a bias in how welfare is assessed, with an emphasis on assessing the resources of an animal’s environment

(Whitham and Wielebnowski, 2013). Does the environment meet the needs of the individual based on the understanding of the species’ biological and physical needs? Is there enough room to move, access to food and water, shade and shelter, etc.? What are the best practices used by the caretakers of that species? Unfortunately, even if these questions are addressed and answered to the best of our knowledge, this does not guarantee good welfare (Barber, 2009; Whitham and Wielebnowski, 2013). Animals of

the same species may react differently to the same environment (Barber, 2009;

Fischbacher and Schmid, 1999; Whitham and Wielebnowski, 2013). Also, addressing

negative welfare may not inherently promote positive welfare (Boissy et al., 2007). The cultural realization of this conundrum has shifted the focus of welfare to include the experience of individual animals; to look specifically at negative and positive welfare through the individual’s negative and positive affective states (for review: Whitham and

Wielebnowski, 2013). Modern views of animal welfare now consider quality of life, which requires consideration of the individual perspectives and preferences of the animal

(Boissy et al., 2007; Mench, 1998; Yeates and Main, 2008), and life worth living, i.e., whether the positive experiences of the individual animal outweigh the negative experiences over the course of its lifetime (Yeates, 2011). Humans are making positive progress in the way we think about animals under our care, and zoos have changed concurrently to reflect shifting societal views by increasing institutional oversight and programs to assess welfare concerns, and by increasing efforts to develop tools for environment- and individual-based welfare assessments.

1.2 Animal Welfare in Zoos

Increased public demand for high welfare standards in zoos (WAZA, 2005) has stimulated a number of changes at the level of the World Association of Zoos and

Aquariums (WAZA), and at the national level (e.g., the Association of Zoos and

Aquariums (AZA) in North America). In AZA, an Animal Welfare Committee was established in 2000 and challenged with developing tools to assess welfare. These tools would come to focus on both welfare inputs - the manipulable features of the animal’s

environment, provided for them by caretakers – and welfare outputs – the behavioral and

physiological responses of the animal to their environment (Barber, 2009). Measuring welfare inputs allows for the evaluation of “welfare potential”, or the potential for animals to make choices and express functional behaviors that allow them to cope with challenges in their environment given the enclosures current conditions. Measures of welfare output allow researchers to assess whether that potential is actualized (Barber,

2009).

Additionally, Animal Care Manuals have been a response by AZA to the resource and environment-based welfare assessments at the population level (Barber, 2009;

Whitham and Wielebnowski, 2013). They are written by experts on the taxonomic group detailed in the manuals, and include information on the currently known needs and best practices for each group (e.g., suggested enclosure size and features, social groupings and nutritional needs; Barber, 2009). Zoos also have an Institutional Animal Welfare Process

(required for accreditation by the AZA) that acts to review and address possible welfare concerns (AZA, 2013). However, specific assessments are needed to determine whether welfare and animal care standards are improved because of these changes.

Unfortunately, this is the least standardized aspect of the process (Whitham and

Wielebnowski, 2013).

1.3 Behavioral Evaluations of Animal Welfare

There are several different types of behavioral measures used to help determine if zoo-housed animals have good welfare. These include ratings scales on the animals’ behavior and/or subjective experiences (Kuhar et al., 2006; Less et al., 2012), behavioral

tests (Carlstead et al., 1999; Shepherdson et al., 2013), and behavioral observations

(Fischbacher and Schmid, 1999; Maslak et al., 2013). Each of these methods has

strengths and weaknesses, and a combination of these methods is often used when trying

to determine the welfare status of an individual (Less et al., 2012; Shepherdson et al.,

2013).

Ratings scales use the people most familiar with the animals, often zoo keepers,

as proxies for the animals, and they are required to make judgments on the behavior

and/or subjective experiences of the individuals (e.g., Kuhar et al., 2006; Less et al.,

2012). These qualitative assessments are cost-effective, reliable (both in terms of test-

retest reliability with the same observer, and in terms of inter-observer reliability) and have been validated in multiple species (Whitham and Wielebnowski, 2013) including black rhinos (Carlstead et al., 1999) and gorillas (Kuhar et al., 2006; Less et al., 2012).

Therefore, they can be a fast, easy method to facilitate multi-institutional studies that seek

to collect behavioral or activity data across a large sample population (Less et al., 2012).

This data can also be used to correlate aspects of the environment that affect welfare or to

identify personality types within a species that are better able to cope with stressors

related to the zoo environment (Carlstead et al., 1999). They can also be used to quantify

subtle differences in behavior, posture, and attitude that reflect changes to an individual’s

health and welfare status, detected by keepers who are intimately familiar with the animal

but not captured by systematic behavioral observation (Whitham and Wielebnowski,

2009). However, because ratings scales should be validated for each new behavior for

each species (Gosling, 2001), behavioral data collection is preferred to detect changes

across a complex suite of behaviors (Less et al., 2012).

Behavioral tests are also used to assess temperament. Different criteria, such as the time to approach a novel object, are used to determine personality traits that are then correlated with other behavioral indicators of welfare, both negative, such as stereotypic behaviors, and positive, such as exploratory behaviors. For example, Shepherdson et al.

(2013) observed the responses of polar bears (Ursus maritimus) to a novel object, and bears who demonstrated more positive interest in the novel object paced less frequently than those who were slower to approach the object (Shepherdson et al., 2013). Because frequent stereotypic pacing is an indicator of negative welfare (Mason and Latham,

2004), individuals who were slow to approach the novel object are more likely to be experiencing poor welfare. Although behavioral tests can be a quick method to identify animals and personality types that are likely to experience poor welfare, they should also be validated for each new species (Carlstead et al., 1999; Shepherdson et al., 2013) and are limited to describing an individual’s behavior in response to a very specific, manufactured situation, limiting their usefulness.

Behavioral observations are perhaps the backbone of behavioral measures, as both keeper ratings and behavioral tests must be validated using behavioral observations under normal conditions. Behavioral observations can be used to describe the typical behavior of a species, or make inferences about the general effects of a condition change at the species or higher taxonomic level [e.g., the effects of construction (Chosy et al., 2014;

Powell et al., 2006), environmental enrichment (Bashaw et al., 2003; Quirke and O’

Riordan, 2011), or large-scale enclosure changes (Fischbacher and Schmid, 1999; Maslak et al., 2013)], as well as the behavioral response of the individual in relation to its environment (Carlstead and Seidensticker, 1991). There are multiple methods of

behavioral data collection that involve recording behaviors as events (recorded at an instantaneous time point, e.g., the onset of the behavior) and states (timing the duration of the behavior, or the onset and termination points), and both individual focal-animals and

groups can be observed. Nested within those categories are ad libitum sampling (often

field notes), continuous sampling (including all occurrence of some behaviors within a

group, continuous recording of the focal-animal’s behavior, or sequence sampling) and

time sampling methods (includes one-zero sampling and instantaneous sampling). The appropriate uses of these methods are detailed in other sources (Altmann, 1974; Dow et al., 2006).

1.4 Using Behavioral Data to Inform and Assess Improvements in Animal Welfare

Whether zoos are hoping to make improvements for species they already care for, or are bringing in a new species that will require new sets of husbandry guidelines and practices, it is good to start with the known ecology and behavior of the species in combination with reviewing current best practices and their influence on behavior (Hill and Broom, 2009). In this way, caretakers can determine which natural behaviors the animals might be highly motivated to perform or need to perform in to maintain good health and well-being, and whether their natural behavioral biology increases their risk of experiencing poor welfare under human care (Clubb and Mason, 2007; Hill and Broom,

2009). Once knowledge of the natural history is combined with current best practices to institute a new husbandry regiment, it is important to evaluate these practices (Clubb and

Mason, 2007; Fraser, 2009; Mason et al., 2007). At that point, zoo researchers and animal caretakers may look at the individual’s positive and negative behavioral indicators

of welfare in addition to other individuals at multiple institutions to help assess individual

welfare (Hill and Broom, 2009). It is also useful to compare the range of activity in zoo-

housed animals to their wild counterparts (Hill and Broom, 2009). If knowledge of wild

behavior is lacking, evaluating levels of inactivity, stereotypic behavior, and active

behaviors/behavioral diversity of the individuals may provide insight into the welfare of

an individual and form the basis for behavioral assessments (Hill and Broom, 2009). The

next chapter will focus on the behavior of bears, the subject of this thesis, in the wild and

in zoos, and how that knowledge can be used to improve welfare.

2. Bear Biology and Behavior

2.1 Behavior in the wild

Bears in the wild tend to have large home ranges, with giant pandas (Ailuropoda

melanoleuca) and polar bears at the extreme opposite ends of the range (5-15 km2 vs.

20,000-250,000 km2, respectively). Inter- and intraspecific variation in home range size appears to be driven by the distribution of resources, although other factors such as sex

(males tend to have larger home ranges) come into play. Bears in larger home ranges

typically have scattered, small, low-nutrient quality food sources, and the percentage of their home range they use at any one time fluctuates with seasonal food availability and other factors, such as the presence of conspecifics (Garshelis, 2004; Joshi et al., 1995;

Spady et al., 2007).

To meet energy needs in low-nutrient quality habitats, bears actively forage for large portions of the 24-hour day. Although information in the wild is lacking for several bear species, those in the middle of the home range spectrum, such as black bears (Ursus

7 americanus), brown bears (Ursus arctos), and sloth bears (Melursus ursinus) may forage for around 40% of the day, and when combined with other behaviors such as playing and fighting, remain active for approximately 50% of the 24-hour day (Clubb and Mason,

2007). Spectacled bears (Tremarctos ornatus), also in the middle of the home range spectrum, are thought to be active 53% of the time, foraging for 70% of that time

(García-Rangel, 2012). Therefore, providing opportunities for zoo-housed bears to forage for long periods on small amounts of low-nutrient quality food may be important to promote good welfare. However, the way bears forage varies among species, requiring special consideration for the care of each species in zoos. Most bear species climb (the exceptions being North American brown bears and polar bears). Some brown bears and black bears rely heavily on fishing in the wild and myrmecophagous, or “ant-eating”, sloth bears have a sucking style of feeding they use to extract ants and termites in the wild after scratching through the bark of trees or the hard earth around termite mounds

(Garshelis, 2004).

The behavior of temperate and tropical bear species are affected by season, however the way these effects manifest themselves in the individual can be influenced by resource and other external and internal conditions, e.g., intraspecific competition and anthropogenic pressures (Beckmann and Berger, 2003; Garshelis, 2004; Spady et al.,

2007). For example, bears are generally thought to be crepuscular (active during dawn and dusk) but are known to shift their activity patterns based on seasonal food availability, human pressures, inter- and intraspecific competition, and predation threats to be either primarily diurnal or nocturnal (Beckmann and Berger, 2003; Bridges et al.,

2004; Garshelis and Pelton, 1980; Vaughan, 2009). Black bears in Great Smoky

Mountain National Park, for instance, were observed to be crepuscular during the spring,

but shifted to more diurnal activity in the summer when berries were highly available.

They shifted again during the hard acorn mast of the fall to primarily nocturnal activity

(Garshelis and Pelton, 1980). The addition of anthropomorphic food sources in

temperate areas can also change bear behavior. Beckmann and Berger (2003) observed

that urban black bears in Nevada feeding off anthropomorphic food sources were active

for fewer hours compared to nearby bears living off wild food sources, that their activity

shifted to nocturnal time periods, and that they had a shorter hibernation period.

Species found in both temperate and tropical areas may have different behavioral

and physiological profiles dependent on their latitude, and tropical bears housed in

temperate areas of North America show seasonal profiles different from their wild

counterparts (García-Rangel, 2012; Garshelis, 2004; Spady et al., 2007). It is well known

that black (Bridges et al., 2004; Spady et al., 2007), sloth and brown bears (Garshelis,

2004; Spady et al., 2007) have summer reproductive seasons that typically last from late

May through August. Although polar bears also exhibit seasonal breeding (Garshelis,

2004; Spady et al., 2007), their season is approximately six weeks earlier than black and

brown bears. Sloth bears in the southern end of their range have a less defined

reproductive season, more similar to the aseasonal, tropical Andean bears, who are only facultatively seasonal at temperate latitudes (García-Rangel, 2012; Spady et al., 2007).

Males and females of all bear species are known to mate with multiple partners

(Garshelis, 2004), and all but polar bears will exhibit tree and scent marking during the

breeding season (Burst and Pelton, 1983; Garshelis, 2004). Female black bears in estrous

will perform approach behaviors towards males, and enter lordosis (immobilization)

when receptive to the male for mounting (Boone et al., 2004; Burst and Pelton, 1983),

and courtship in Andean bears can involve play and high-pitched vocalizations from both

sexes (García-Rangel, 2012).

The social behaviors of Andean bears (García-Rangel, 2012; Peyton, 1980), polar

bears (Atkinson and Ramsay, 1995), black bears (Rogers, 1987), and other species seem

to be influenced by resource conditions and/or genetic relatedness. Although they are generally solitary (Garshelis, 2004), these species are known to associate in groups around areas of high food abundance. Rogers (1987) observed adult black bears in

Minnesota tolerating conspecifics within two meters around garbage dumps, and play was commonly observed in bears under five years old. Genetic relatedness may influence the spatial structure of these groups, as brown bears show significant correlation between relatedness, overlap in home range size and tolerance of close proximity (Støen et al., 2005). Bears may also follow conspecifics from neighboring winter or summer ranges to the same feeding or denning sites, respectively, using shared travel routes and even travelling loosely together, a process that seems to be mediated through chemical communication (Noyce and Garshelis, 2014). Although bears are not known to be overtly territorial (Garshelis, 2004), aggression may occur between males over competition for mates, and between females and/or males over scarce food resources or protection of young (Costello et al., 2009; García-Rangel, 2012; Garshelis, 2004).

2.2 Behavior in Zoos

Because bears show great phenotypic plasticity in the wild, this may suggest that humans have flexibility in the way that they manage bears under their care. For example,

because bears can show diurnal, crepuscular, or nocturnal activity patterns based on

resource and other environment conditions (Garshelis, 2004), bears may readily adapt to

the diurnal schedule of zoo keepers. In spite of this apparent flexibility, it is important to

evaluate and understand bear behavior in zoos to determine the effect of the zoo

environment on welfare (Whitham and Wielebnowski, 2013).

Behavioral indicators of negative welfare include, but are not limited to, stereotypic behaviors, self-injurious behaviors, and even excessively high levels or out-

of-context performance of some natural behaviors, sometimes termed compulsive or

displacement behaviors (Barber, 2009; Mason, 2006; Melfi, 2009; Vickery and Mason,

2004; Whitham and Wielebnowski, 2013). For example, self-directed behaviors and

grooming may become excessive self-body manipulation or excessive grooming of a social partner (Mason, 2006). Similar to stereotypic behaviors, compulsive behaviors seem to be driven by a variety of underlying factors, including frustrated goal-oriented behaviors (performance of the behavior does not lead to achieving the goal, e.g., eating or mating), social and other stressors, and deprivation, and if unchecked, may develop into stereotypies (Mason, 2006). Context is key with this last class of behaviors, as self- directed behaviors and grooming in bears may also increase in response to the breeding season (Carlstead and Seidensticker, 1991; Swaisgood et al., 2003).

In a review of the literature, stereotypic behaviors were reported to be associated with decreased welfare in 68% of cases in humans, farm, laboratory and zoo animals

(Mason and Latham, 2004). Clubb and Mason (2003) found that bears and other carnivores with large home ranges are especially prone to stereotypic behaviors. The evidence supporting this finding in bears has increased with continued research.

Swaisgood and Shepherdson (2006) found in their meta-analysis that bears spend ≈

12.4% of their time exhibiting stereotypic pacing. Of the different bear species,

spectacled bears seem to exhibit some of the highest levels, with individuals performing

stereotypic behaviors for a median of 52% of observation time, followed by polar bears

(37%), sloth bears (17%), black bears (16%), brown bears (12%), and giant pandas (7%;

Clubb and Mason, 2007). Therefore, even within this taxonomic group, some species

appear to be at increased risk of compromised welfare in zoos, and may need to be

prioritized for targeted interventions (Mason et al., 2007).

Within any given species, the characteristics (timing, location and form) of

stereotypic behaviors can help hint at underlying drivers, and therefore, the most effective

treatments (Swaisgood and Shepherdson, 2005). Given the link between large home

range and foraging effort in wild bears, it is not surprising that there also seems to be a

link between foraging opportunities and stereotypic behavior in zoo-housed bears. For

example, Carlstead and Seidensticker (1991) found that pacing increased during the fall

in a male black bear, a time correlated with seasonal increases in food consumption in

wild black bears. Furthermore, pacing became increasingly oriented inwards toward the

area in which he was fed and shifted from post- to pre-feeding time compared to the

summer reproductive season. Vickery and Mason (2004) also observed that stereotypic

behaviors in Malayan sun bears (Helarctos malayanus) and Asiatic black bears (Ursus

thibetanus) were oriented towards food-delivery areas, with the frequency of stereotypic behaviors increased near feeding time. Finally, stereotypic behaviors were more common around feeding time in brown bears (Montaudouin and Le Pape, 2005). In this

last case, the amount of food did not appear to be related to the performance of

stereotypic behaviors, and hunger was not likely a factor.

The form of stereotypic behavior can also be used to help indicate the underlying

drivers. Locomotory stereotypic behavior in bears is primarily associated with appetitive

(or searching) behaviors, and they have been linked to, among other things, searching for compatible mates (Bauer et al., 2013; Carlstead and Seidensticker, 1991; Fischbacher and

Schmid, 1999), searching for appropriate resting spots (Fischbacher and Schmid, 1999), and searching for foraging opportunities (Carlstead and Seidensticker, 1991; Vickery and

Mason, 2004). Looking only at the form may not provide a clear indication of how to relieve possible underlying factors. However looking at the timing of these behaviors, may provide more information (Swaisgood and Shepherdson, 2005; Vickery and Mason,

2004). Did the frequency of stereotypic behaviors increase before feeding time? This might indicate frustrated foraging or anticipatory behavior (Vickery and Mason, 2004;

Watters, 2014). Did the male just have an aggressive encounter with the female, and/or is it their reproductive season? It is likely frustrated reproductive behavior (e.g.,

Fischbacher and Schmid, 1999). Is it raining, or are there currently temperature extremes? The animal may be seeking shelter (Fischbacher and Schmid, 1999).

Therefore looking at the form, other characteristics of the stereotypic behavior, and events prior to and post-performance of these behaviors is critical.

Although locomotory, stereotypic behaviors performed prior to feeding time may indicate negative affect from a lack of foraging opportunities, a focus on anticipatory behavior in the last few years warrants a close look to determine whether this may actually be an indicator of positive affect. Although anticipatory behaviors can be as

simple as an increase in activity prior to an event, they can also be similar in form to

stereotypic behaviors, e.g., pacing (Watters, 2014). However, animals performing

stereotypic behavior may be hard to distract, disengaged with their environment, have

low hanging heads, and invariant pacing bouts that last for at least three repetitions (Cless

et al., in press) while animals performing anticipatory behavior seem to be looking for

signals that indicate the event they are anticipating (Watters, 2014). An animal pacing in

anticipation of receiving food or gaining access to off-exhibit areas may therefore frequently pause or break their bout pattern to look toward the shifting area or to detect any sights or sounds that indicate keeper presence. An animal performing anticipatory behavior related to a positive event such as feeding time is considered to be in a positive affective state. However, the quality and duration of anticipatory behaviors may indicate the overall welfare status of the individual (Watters, 2014). Animals that are deprived

and unenriched are highly sensitive to perceived rewards and are likely to perform long,

intense bouts of anticipatory pacing at a low frequency (Watters, 2014). For instance, an

underfed bear that consistently receives food at 1700 may have an intense bout of

anticipatory pacing starting at 1500 that lasts for two hours, during which they repeatedly

pause or break the pattern. A bear that frequently receives foraging opportunities may

demonstrate frequent, but short and low intensity bouts prior to each anticipated event.

Therefore, the overall welfare status of animals performing anticipatory behaviors can

range from good to bad, even if they have positive affect during performance (Watters,

2014).

Behavioral measures of negative welfare alone may not fully indicate the health

and welfare of an individual; animals can be good at hiding obvious sign of pain and

distress (Hill and Broom, 2009), and as previously mentioned, individuals react differently to similar environmental conditions (Dawkins, 2001). Therefore, the absence

of undesirable behaviors, such as stereotypic behaviors and self-injurious behaviors, does not necessarily indicate good welfare (Melfi, 2009). However measuring multiple behavioral indicators of both positive and negative welfare is a cost-effective and efficient tool for assessing the welfare status of an individual (Hill and Broom, 2009).

Zoo-housed bears experiencing good welfare will typically express a high diversity of natural behaviors, e.g., reproductive, affiliative (play, grooming, rest-in- contact) and exploratory behaviors, that can be very similar to behaviors performed in the wild (e.g., Mason et al., 2007). However, whether or not these behaviors can be performed, at what frequencies, and whether they lead to functional consequences depends heavily on the environment provided for them. For example, although most bear species climb in nature, their ability to do so in zoos is dependent on the provision of climbing structures (e.g., Renner and Lussier 2002). Again, the ability of brown bears and black bears to fish as in the wild is dependent on whether they are provided with pools and live fish. Myrmecophagous sloth bears may benefit from opportunities to suck honey out of logs (to stimulate the sucking style of feeding they use to extract ants and termites in the wild), or search for insects and other food in hollowed-out trees that are placed into their exhibits (Anderson et al., 2010; Garshelis, 2004). Bears may also rest,

play, breed, and scent-mark, but like other natural behaviors, the expression of these

behaviors is heavily dependent on the provision of suitable social partners, enrichment,

resting spots, and other environmental factors in the hands of their caretakers

(Fischbacher and Schmid, 1999; Mason et al., 2007; Swaisgood and Shepherdson, 2006;

Vickery and Mason, 2004).

Although performance of these behaviors may be inherently reinforcing, they are

more likely to increase and the animals are more likely to experience positive welfare

when these behaviors are reinforced by functional consequences to their expression

[escape behaviors lead to perceived safety, exploratory behaviors lead to foraging, mating

or social opportunities, etc.; (Boissy et al., 2007; McGowan et al., 2010; Swaisgood,

2007)]. Comparing the diversity and frequency of these behaviors to animals living

under good conditions in the wild and in zoos can be a useful way to assess the current

welfare state of an animal (Hill and Broom, 2009). In fact, Barber (2009) suggested that

keeping track of positive welfare indicators as “green flags” (including high levels of

play behavior, reproductive behaviors and success, and demonstrated social competency)

in combination with “red flags” (e.g., high levels of aggression, self-injurious behaviors, and maternal neglect) could help assess the welfare of individuals across a given population through epidemiological studies.

Shifts in an animal’s positive welfare status can be assessed by determining whether environmental changes are associated with changes in these positive behavioral measures within an individual (Whitham and Wielebnowski, 2013). However, some natural behaviors can indicate either improved or decreased welfare. For instance, while

Swaisgood (2003) described increases in bleating and scent marking as functionally significant for female giant pandas preparing to mate (an indicator of positive welfare), giant pandas also exhibited more scent marking, bleating and grooming during construction days, concurrent with increased stereotypic behaviors (an indicator of

negative welfare; Powell et al., 2006). Because the performance of some behaviors may similarly change in response to opposite shifts in welfare status, this complexity reinforces the need for multiple, reliable behavioral measures of positive and negative welfare when assessing the welfare state of an animal.

2.3 Effects of the Environment on Behavior and Welfare

There are several aspects of the zoo environment, other than the way zoo-housed

bears are offered food, that can affect welfare and behavior, e.g., social grouping, the rearing environment, and size and features of the enclosure (Montaudouin and Le Pape,

2005; Shepherdson et al., 2013). The effects of social environment can be complex. In one study, for example, the size of social groupings was not correlated with the level of stereotypic behavior in brown bears; however, there were lower levels of aggression and more play behaviors in groups of two, compared to larger groups (Montaudouin and Le

Pape, 2005). Conversely, in the closely related polar bear, bears in larger groups performed fewer stereotypic behaviors (Shepherdson et al., 2013).

Another form of the social environment, early rearing experience, may also affect

the behavior of many bear species. Although Shepherdson et al. (2013) found that the

age at which polar bears were separated from their mother had no effect on their levels of

stereotypic behavior, hand-rearing was associated with increased levels of abnormal and

stereotypic behaviors in sloth bears (Forthman and Bakeman, 1992), and Pajetnov and

Pajetnov (1995) observed that orphaned brown bear cubs demonstrated abnormal, self-

directed hand-sucking behaviors and were more irritable, reactive and inactive.

Furthermore, the compulsive and stereotypic behaviors performed by a male sloth bear,

began developing shortly after early weaning and rejection by his mother (Bauer et al.,

2013).

The size and features of the enclosure also affect the potential for an animal to experience good welfare. A view out of the enclosure was associated with reduced

stereotypic behaviors in both polar bears (Shepherdson et al., 2013) and brown bears

(Montaudouin and Le Pape, 2005), but enclosure size did not appear to effect these

behaviors in either study. Increased enclosure size was, however, associated with

decreased frequencies of stereotypic behaviors in giant pandas (Liu et al., 2003), although

no other behaviors (including foraging, playing, grooming, marking, resting, exploring

and locomotion) were affected. A number of other environmental factors seem to affect

behavior in bears. In one study, brown bears with medium or large pool areas in their

exhibit performed less stereotypic behavior than bears with small pools (Montaudouin and Le Pape, 2005). Other researchers found that loud ambient noise levels were

associated with increased locomotion, door-directed behaviors, scratching and agitated

vocalizations in pandas (Owen et al., 2004). Access to both on- and off-exhibit areas was

associated with less stereotypic behavior in adult brown bears (Montaudouin and Le

Pape, 2005) and reduced stereotypic behavior in sun bears (Rog et al., in review) and polar bears (Ross, 2006), additionally increasing social play in the latter. In pandas, access to on- and off-exhibit areas has also been shown to reduce agitated behaviors , which was a composite category that included stereotypic pacing, door-directed behaviors and scratching (Owen et al., 2005).

3. Promoting Positive Affective States

There are various ways to reduce the expression of behaviors that indicate

negative welfare (for review: Mason et al., 2007). Selective breeding of individuals that

don’t perform stereotypic behavior has worked in mink farming systems (Hansen et al.,

2010), however this method may genetically select against behaviors that are important if

these species were to be reintroduced into the wild (Mason et al., 2007). Furthermore,

stereotypic behaviors may serve as a coping mechanism. In exhibits with poor conditions

that induce indicators of fear, stress, and/or depression, individuals that are inactive and

do not exhibit stereotypic behaviors often have poorer welfare than those that do exhibit

stereotypic behaviors (Mason and Latham, 2004). In these situations, some stereotypic behaviors seem to have “mantra effects” (Mason and Latham, 2004), and the repetition may actually help the animal mitigate its stress response, as non-stereotyping animals in

these exhibits are often less able to cope, with no repetitive movements to help calm

them. Therefore, by not addressing the underlying environmental conditions resulting in

poor welfare, there is a risk that the animals selected for will have decreased welfare

without stereotypic behaviors to help cope (Mason and Latham, 2004). Pharmaceuticals

could potentially be useful while attempting to address the underlying frustrations.

Yalcin and Aytug (2007) treated a male brown bear with fluoxetine (a selective

serotonin-reuptake inhibitor) for six months to abolish stereotypic pacing, after which

time the bear was transferred to a larger, naturalistic enclosure and did not resume pacing

while observed over the next year. Although pharmaceuticals may therefore reduce

behavioral indicators of negative welfare, they do nothing to improve the underlying

environmental conditions and may best be used in combination with efforts to address

possible underlying stressors. They can also have undesirable side effects; although

fluoxetine reduced pacing and fur-picking in one polar bear (Poulsen et al., 1996), it seemed to exacerbate stereotypic behavior in another bear (Poulsen et al., 1998).

Punishment or physically blocking the stereotypic behavior may also reduce overt behavioral signs of negative welfare (Mason et al., 2007), but may further reduce welfare, and again do not address the underlying cause (Ödberg, 2006). Therefore, enrichment is typically the preferred method to both decrease these indicators of negative welfare, while simultaneously promoting positive affective states (Mason et al., 2007).

3.1 The Use of Enrichment in Zoos

Enrichment is broadly defined as changes to zoo habitats that provide animals with opportunities to perform behaviors important for their physiological and psychological well-being (Swaisgood and Shepherdson, 2005). These opportunities were typically either absent or not provided for at sufficient frequencies prior to enrichment, and lead to functional consequences for the behavior performed (e.g., digging behavior in a leaf-filled tub that leads to an armadillo finding worms). Because of this broad definition, it is easy to understand why enrichment is the recommended way to promote positive affective states in animals and to improve welfare (Mason et al., 2007). For example, the USDA Animal Welfare Act and Regulations [Blue Book] requires that the environment of the primary enclosure “be enriched by providing means of expressing non-injurious, species-typical activities”. It also stipulates that enrichment should be species-appropriate, taking into account taxonomic differences (USDA, 2013). The Polar

Bear Care Manual also recommends the use of complex exhibit designs, variable feeding

strategies and enrichment (especially moveable items that can be rearranged daily)

because of their association with decreased stereotypic behavior (AZA Bear TAG, 2009).

There are many different types of enrichment including, but not limited to,

substrate and scent enrichment, barriers and landscaping, climbing structures, cognitive

challenges, schedule changes and enclosure rotations, food processing (e.g., whole fruits

and carcass feeding), and, some would argue, positive reinforcement training (Swaisgood and Shepherdson, 2006; Westlund, 2014). Although not always employed to elicit species-typical behavior, positive reinforcement training may be considered enriching because of its use in permitting cooperative husbandry procedures or medical treatment, thereby reducing stress and increasing psychological wellbeing. Feeding enrichment is a category that can integrate a variety of approaches but by definition requires intrinsic food reinforcement. For example: positive reinforcement training often utilizes a food

reward; food is often buried in substrate to increase search time; food may be delivered at

the top of climbing structures to encourage use; puzzle feeders are also cognitive

challenges; and variable feeding times require schedule changes.

Unfortunately, it is unclear whether certain types of enrichment are more effective

in certain situations. Many effective enrichment studies have combined multiple

enrichment types; however, this has made it difficult to determine if one type of

enrichment is more effective than others (Shyne, 2006; Swaisgood and Shepherdson,

2005; 2006). Therefore, although the importance of offering high rates of multiple

enrichment items and types was seen by Shepherdson et al. (2013) as one of the key

factors for reducing pacing in polar bears, it is recommended that enrichment research

focus on one type of enrichment at a time (Swaisgood and Shepherdson, 2005).

3.2 The Effects of Enrichment on Behavior and Welfare

Swaisgood andShepherdson (2006) conducted a meta-analysis on stereotypic behavior, looking at the effects of different types of enrichment grouped into four enrichment principles, mimicking nature, environmental complexity, sensory stimulation and foraging challenge. Foraging challenge was further divided into three types, those to increase food searching, the extraction of food from an item, or the time it took to process food. Although they found that there was no difference in the four enrichment principles or feeding enrichment types, they did find some encouraging results that greatly support the use of enrichment to decrease negative welfare. Stereotypic behavior was reduced in

53% of studies by 50-60% regardless of the taxonomic group, demonstrating that a wide variety of animals are responsive to enrichment changes. Furthermore, enrichment programs that lasted for longer periods effected greater reductions. Another meta- analysis by Shyne (2006) reported that 90% of enrichment studies show evidence of reduced stereotypies, supporting the findings by Swaisgood and Shepherdson (2006).

Unfortunately, stereotypic behavior was not extinguished in any of the studies included in the analysis by Swaisgood and Shepherdson (2006), indicating that either large-scale environmental and husbandry changes may be required to abolish stereotypic behavior, or that there may be underlying morphological changes to the central nervous system that resist the ability of environmental changes to eliminate stereotypies. At least in some cases, it may be the latter. Fischbacher and Schmid (1999) found that moving

Andean bears to a large new exhibit enriched with varying substrates, plants, water features, climbing structure and feeding devices failed to eliminate stereotypic behavior in the two bears with established stereotypic behaviors, but a young female never

developed stereotypic behaviors under these conditions. However, a later study on two

Andean bears transferred to a large, naturalistic enclosure and scatter fed at several unpredictable times found that these changes completely eliminated stereotypic behavior

in one bear, and that a combination of the move and dental treatment greatly reduced

stereotypic behavior in the other, indicating that major environmental and husbandry

changes can result in complete elimination of stereotypic behavior (Maslak et al., 2013).

Stereotypic and agonistic behaviors can be increased by unpredictable feeding

schedules, as seen in macaques (Waitt and Buchanan-Smith, 2001), which is thought to

be due to frustration by signals from their caretakers (such as the sounds of unlocking

doors or food preparation) that no longer reliably precede feeding time. Unpredictable

schedules can have other negative effects as well. Although capuchin monkeys put on an

unpredictable feeding schedule demonstrated less abnormal and self-directed behavior

(often associated with stress or anticipation in primates), they appeared to be less social,

spending less time in proximity and engaging in affiliative behaviors, and were more

inactive before feeding time (Ulyan et al., 2006). However, in their review on the effects

of predictability on captive animals, Bassett and Buchanan-Smith (2007) argue that it is likely the signaling unpredictability and not the inherent temporal unpredictability of the

schedule that result in these undesirable effects, and recommend the use of unpredictable

feeding schedules due to evidence of increased natural behaviors. They suggest that a

novel and distinguishable reliable signal (such as a bell) should precede feeding in place

of the less reliable signals. Montaudouin and Le Pape (2004) found that only brown

bears currently or historically housed in institutions where keepers fed them from visitor

areas performed stereotypic behaviors regardless of feeding schedule, suggesting a

23 simple change in feeding style that reduces unintentional signaling by keepers may help avoid increases in undesirable behaviors. This hypothesis is supported by findings that red foxes (Vulpes vulpes) fed at unpredictable times from automatic feeders showed no overt signs of frustration, and had reduced stereotypic behaviors compared to baseline, possibly because the automatic feeders avoided unreliable signaling associated with the keepers. Additionally, a variable feeding schedule reduced pacing in cheetahs (Acinonyx jubatus; Quirke and O’ Riordan, 2011), and a later multi-institutional study found that predictable feeding schedules were positively correlated with higher levels of pacing than unpredictable schedules in cheetahs (Quirke et al., 2012). In addition to unpredictable feeding schedules, other enrichment such as a climbing structure combined with feeding enrichment in Andean bears (Renner and Lussier, 2002), carcass feeding (Mcphee, 2002) and live fish and leg bones (Bashaw et al., 2003) in large cats, honey logs in sloth bears and one black bear (Anderson et al., 2010; Carlstead et al., 1991), and positive reinforcement training in polar bears (Shepherdson et al., 2013) have all been associated with lower levels of stereotypic behaviors compared to unenriched conditions.

Stereotypic behavior is not the only behavioral indicator of welfare, and enrichment is known not only to decrease the frequency of stereotypic behavior, but to increase behavioral signs of positive welfare. Natural behaviors were increased in 13 of

16 studies reporting this behavioral category across multiple mammalian and avian taxa in the meta-analysis by Swaisgood and Shepherdson (2005). Activity levels (not including abnormal behaviors) also increased in 14 of 19 studies in this analysis, and in a number of experimental studies. For example, exploratory and foraging behaviors were increased by automatic feeders in red foxes (Kistler et al., 2009). The climbing structure

24 combined with feeding enrichment in Andean bears also increased overall activity levels

(Renner and Lussier, 2002), along with horse leg bones in lions (Bashaw et al., 2003), while carcass feeding increased foraging time in large cats (Mcphee, 2002). Although honey logs had no effect on overall activity in bears in the study by Carlstead et al.

(1991), they seemed to replace walking and pacing with functional foraging behaviors in the sloth bear, and effectively increased exploratory behaviors in other sloth bears

(Anderson et al., 2010). The variable feeding schedule introduced by (Quirke and O’

Riordan, 2011), not only reduced stereotypic behaviors in cheetahs, but increased exploratory behaviors as well. Finally, behavioral diversity increased in all three enrichment studies analyzing that measure in the review by Swaisgood and Shepherdson

(2005), and was also increased in Andean bears (Renner and Lussier, 2002), red foxes

(Kistler et al., 2009), and cheetahs (Quirke and O’ Riordan, 2011).

Although Swaisgood and Shepherdson (2006) found no differences in the type of enrichment on its ability to reduce stereotypic behavior, they suggest that this finding was confounded by a number of factors, including species differences and taxonomic order

(e.g., primates were the only ones given extraction feeding enrichment). For instance, researchers may have chosen to study what they thought would be the most effective type of enrichment based on the animals’ prior behavior. If they were correct in their assumptions and successfully addressed the underlying stressor, the enrichment types in each study would be similarly effective (Swaisgood and Shepherdson, 2006). That is, feeding enrichment used when frustrated foraging opportunities are the underlying stressor may be equally effective to scent enrichment when frustrated mating opportunities are the underlying stressor. Further evidence that one specific enrichment

type can more successfully address stereotypic behavior than other types is that when

multiple types of enrichment are combined as the treatment, they are not necessarily more

effective than when single enrichment types are offered (Swaisgood and Shepherdson,

2006).

Some experimental studies have demonstrated the benefits of tailoring enrichment to the suspected underlying motivation. For instance, it was mentioned previously that stereotypic behavior changed seasonally in the black bear studied by Carlstead and

Seidensticker (1991) from post- to pre-feeding. Pacing also became increasingly oriented inward towards the keeper and feeding area and increased, all concurrently, with the shift

from the summer breeding season to the fall hyperphagia season of wild black bears.

During the summer, feeding enrichment slightly reduced pacing, but not as significantly

as scent enrichment, and failed to increase exploratory/foraging behaviors. Conversely,

when the characteristics of pacing shifted to indicate an underlying foraging motivation,

feeding enrichment almost completely eliminated pacing. In another study examining

pacing in a female sun bear, high levels of agonistic interactions between females

appeared to precede pacing oriented around the indoor holding area. Husbandry changes

that included separation of the two females and access to indoor holding eliminated

pacing in this female (Rog et al., in review). In contrast, another study found feeding

enrichment failed to change any behavior, other than increased foraging around feeding

time in Andean bears (Fischbacher and Schmid, 1999). However, the suspected

underlying driver behind the stereotypic behaviors for the female and male were lack of

suitable resting spots and frustrated social behaviors, respectively, indicating that

enrichment can fail to have the desired effect when it is not tailored to the underlying

motivation.

The inherent food reward in feeding enrichment may bestow benefits beyond

those of other types of enrichment, increasing the long-term attractiveness and

effectiveness of enrichment. For example, hiding preferred food items was more

effective at increasing exploratory behaviors and behavioral diversity than plastic balls in

maned wolves (Chrysocyon brachyurus; Cummings et al. 2007), and brown bears spent more time investigating ice blocks and boxes containing food than ice or boxes alone

(McGowan et al., 2010). Additionally, when bush dogs (Speothos venaticus) were required to extract food from wood piles for 30 consecutive days, they habituated slowly to this enrichment and only demonstrated a 20% decline in interest during this period

(Ings et al., 1997). Refilling honey logs re-stimulated interest in them by sloth bears

(Anderson et al., 2010; Carlstead et al., 1991); this single enrichment item increased exploration and decreased stereotypic behavior six to ten days after the enrichment items were taken away, even after they were presented for five consecutive days.

Although the effects of feeding enrichment have been well studied in bears and other taxa, unpredictable feeding schedules have received little attention in bears. In the cases where they have been implemented (Carlstead et al., 1991; Maslak et al., 2013), the change has been concurrent with other forms of enrichment. In fact, we are aware of no systematic studies attempting to isolate the effects of temporal unpredictability in feeding on bear behavior. Thus, we designed two studies to examine the effects of feeding enrichment on the time budgets and normal behavioral diversity in four species of bears housed at Cleveland Metroparks Zoo. The specific aims of this thesis were as follows: 1)

27 the aim of Experiment One was to test the effects of fixed vs. variable time presentation of “work-for-food” enrichment (enrichment designed to increase the time and effort that bears spend foraging); 2) the aim of Experiment Two was to examine possible habituation effects over a 30-day sustained period of semi-variable enrichment schedule that was adapted based on keepers’ needs and suggestions following Experiment One.

Behavioral observations were conducted using a mutually exclusive and exhaustive ethogram that included indicators of both positive and negative welfare.

Behavioral observations offered several advantages as the method of data collection over rating scales and novel object tests. First, ratings scales are limited in the number of behaviors for which they can be substituted, and they have not been validated for all species in this study. Second, novel object tests were not appropriate to examine the overall effects of an enrichment program. The bears were observed using instantaneous scan sampling on a focal group in order to record the behavior of multiple individuals at the same time. This was possible because of the small group size (a maximum of two individuals in this study) and because the size of the exhibit allowed both individuals to be continuously observed (Altmann, 1974). This method allows for the approximation of time budgets in the individuals of the group. We hypothesized that enrichment would reduce abnormal behaviors and increase exploratory behaviors, visibility and behavioral diversity, and that the magnitude of change compared to baseline would be larger with variable-time compared to fixed-time presentation of enrichment. We also hypothesized that no habituation would occur over the sustained enrichment period as evidenced by increased exploratory behavior, visibility and behavioral diversity, and reduced

28 stereotypic behavior compared to baseline, that were not significantly different when comparing the three successive cycles of 10 days that the enrichment was offered.

Study: Using Behavioral Measures to Assess the Effects of Feeding Enrichment on the Welfare of Four Bear Species

1. Introduction

Bears and other carnivores with large home ranges in the wild are predisposed to high frequencies of stereotypic behavior in captivity (Clubb and Mason, 2003). Because stereotypic behaviors are linked to decreased welfare, Mason et al. (2007) advocates for a zero-tolerance policy of these abnormal behaviors. Environmental enrichment is widely accepted as a way to both reduce stereotypic behavior and increase behavioral indicators of positive welfare in zoo animals. However, when trying to optimize well-being using enrichment, it is important to understand the natural and captive behavior of the species to: 1) Identify the type and frequency of natural behaviors that they are motivated to express (Clubb and Mason, 2007; Fraser, 2009; Hill and Broom, 2009; Mason et al.,

2007); 2) Identify underlying drivers behind stereotypic behaviors that influence the effectiveness of various types of enrichment (Clubb and Mason, 2007); and 3) Predict and assess which targeted interventions were useful in improving welfare (Mason et al.,

2007; Swaisgood and Shepherdson, 2006).

On average, many bear species have large home ranges with energy-limited habitats in which small, and sometimes low-nutrient quality foods are scattered throughout the landscape (Garshelis, 2004; Spady et al., 2007). Therefore, bears frequently spend large amounts of time and energy locating and handling food, and finding mates. Although data on foraging time in the wild are unavailable for many species, a review by Clubb and Mason (2007) reported that on average, brown bears

(Ursus arctos) spend 41% of their time foraging, and along with sloth (Melursus ursinus) and black (Ursus americanus) bears, spend approximately 50% of their time engaged in active behaviors (including foraging, locomotion, playing and fighting). These conditions in the wild suggest that feeding enrichment (enrichment with an intrinsic food reward) designed to elicit active behaviors, especially foraging, may enhance welfare in zoo-housed animals.

Because of the link between large home ranges and foraging effort, it is not surprising that studies investigating characteristics of stereotypic behavior (such as type, timing and location) and their underlying motivation have often linked stereotypies to anticipation of feeding time. For instance, Montaudouin and Le Pape (2004) found that stereotypic behaviors only occurred in brown bears currently or historically housed in parks where caretakers fed bears from visitor areas, and that the frequency of stereotypic behaviors increased near feeding time (Montaudouin and Le Pape, 2004; 2005). Asiatic

black bears (Ursus thibetanus) and Malayan sun bears (Helarctos malayanus) also

displayed intense stereotypic bouts before feeding times, and performed in areas from

which food delivery could be observed (Vickery and Mason, 2004). The motivation

behind these behavior and their relevance to the welfare state of the individual may range

from negative to potentially positive (Watters, 2014). Although these studies may

indicate limited foraging opportunities as a common causal factor of stereotypic behavior

in bears, it is also possible that these bouts are anticipatory behaviors, which may actually

be associated with positive affective states (Watters, 2014). Either explanation suggests

that feeding enrichment may be most effective at reducing these behaviors.

Food rewards, specifically, may also increase long-term attractiveness and

effectiveness of enrichment. Cummings et al. (2007) found that hiding preferred food items (dead mice) was more effective at increasing explorative behaviors and behavioral diversity than plastic balls in maned wolves (Chrysocyon brachyurus), and brown bears spent more time investigating ice blocks and boxes containing food than ice or boxes alone (McGowan et al., 2010). Additionally, animals tended to habituate slowly to feeding enrichment when presented with the same items for many days consecutively, an important factor when trying to design an efficient enrichment program with long-term effectiveness. Bush dogs (Speothos venaticus) presented with food hidden in wood piles for 30 consecutive days only demonstrated a 20% decline in interest (Ings et al., 1997), and sloth bears presented with honey logs for five consecutive days showed some habituation, but still exhibited increased exploration and decreased stereotypic behavior six to ten days after the enrichment items were taken away (Anderson et al., 2010).

There are several types of feeding enrichment, including those designed to make animals “work for food” and increase foraging time (e.g., puzzle feeders), and those designed to add unpredictability of food disbursement in time or space. Work-for-food enrichment has had variable effects on behavior in previous studies. The honey logs presented to sloth bears by Anderson et al. (2010) were effective in reducing stereotypic behavior during the enrichment period and increasing exploration post-enrichment.

Bashaw et al. (2003) found that feeding live fish to Sumatran tigers (Panthera tigris sumatrae) decreased stereotypic behavior by 50% for two days after the feeding.

However, scattering food items in an exhibit, as opposed to piling food, did not change behaviors in brown bears although increased feeding frequency amplified time spent

foraging and time spent active in a study by Grandia et al. (2001). Greater feeding

frequency combined with unpredictable feeding times also increased foraging frequency

in one black bear (Carlstead et al., 1991) and electronic feeders delivering food at

unpredictable times were more effective at increasing foraging time when combined with

scattered feeding than the unpredictable schedule alone in the red fox (Vulpes vulpes;

Kistler et al. 2009). Unpredictable feeding times were also associated with increased

activity and behavioral diversity in red foxes, both alone and combined with scattered

feeding (Kistler et al., 2009), and with less stereotypic behavior in cheetahs (Acinonyx

jubatus; Quirke et al., 2012).

Although Carlstead, Seidensticker, and Baldwin (1991) examined the combined

effects of increased feeding frequency with an unpredictable feeding schedule in one

black bear they did not study either separately, making it impossible to tease apart

potential effects of the unpredictable feeding time. In fact, no systematic efforts to

uncover the effects of unpredictable feeding schedules in bears have been reported.

Therefore, we designed two studies to examine the effects of feeding enrichment on the

time budgets and normal behavioral diversity in four species of bears housed at

Cleveland Metroparks Zoo. The aim of Experiment One was to test the effects of fixed

vs. variable time presentation of “work-for-food” enrichment. We hypothesized that

enrichment would reduce abnormal behaviors (a behavioral indicator of negative welfare)

and increase exploratory behaviors and behavioral diversity (behavioral indicators of

positive welfare). We also hypothesized that the magnitude of change compared to

baseline would be larger with variable-time compared to fixed-time presentation of enrichment. The aim of Experiment Two was to examine possible habituation effects

over a 30-day sustained period of a semi-variable enrichment schedule that was adapted

based on keepers’ needs and suggestions following Experiment One. We hypothesized

that no habituation would occur over the sustained enrichment period as evidenced by

increased exploratory behavior, and behavioral diversity, and reduced stereotypic

behavior compared to baseline, that were not significantly different when comparing the

three successive cycles of ten days that the enrichment was offered.

2. Methods

2.1 Animals and Animal Care

This study occurred from July through November of 2014 and included eight

adult bears (3-22 years old) of four different species maintained in five exhibits at

Cleveland Metroparks Zoo: 1.1 Andean bears (Tremarctos ornatus) were housed singly

for the duration of the study, and 1.1 sloth bears, 2.0 brown bears and 0.2 black bears

were housed as three social groups in single species exhibits. The male and female

Andean bears were fed 0.45 kg and 1.36 kg of Purina Fit & Trim, respectively. The male and female sloth bears were fed 0.45 kg and 0.91 kg of Mazuri Exotic Canine diet, respectively, and 0.23 kg of Purina Fit & Trim dog food. The brown and black bears

were fed 0.91 kg/animal of Purina Fit & Trim and 3.63 kg/animal of Mazuri Exotic

Canine diet, respectively. All bears were fed 0.23-0.45 kg/animal of produce variety

(including apples, oranges, carrots, sweet potatoes, and grapes) and treat items (including raisins, peanut butter and peanuts) daily. Additionally, the brown and black bears were

fed 0.45-1.35 kg/animal of meat a few days/week, including horse knucklebones,

horsemeat, and frozen-thawed herring, capelin or carp. All species received a variety of

enrichment during the baseline period including scents, food scattered by keepers, plastic

manipulable items (sometimes with smeared peanut butter and honey), whole fruit, and

small ice blocks, consistent with their normal care. Each feeding enrichment item

received during the experimental periods was novel to all bears, with the exception of the

ice blocks, and were newly constructed and utilized for Experiments One and Two.

However, the ice blocks in the study were larger (approximately two gallons, compared to one cup), and contained a much larger portion of their diet (approximately 20% by weight, as opposed to 1-5%).

All bears were secured on exhibit from 1000 until 1645 daily, with the exception of the sloth bears, which had continuous access to the indoor holding area. During the baseline period, food was placed in different areas throughout the sloth and Andean bear exhibits in the morning (1000), and bears were fed again when they were brought back into holding at 1645. Black and brown bears were scatter fed (food tossed randomly throughout the space) on exhibit at random times, 4-6x daily, with the first feeding at the time they were first let out in the morning. For the remainder of the scatter feedings, the keepers fed them either from the visitor area or from the roof of the indoor holding area.

The bears were aware of the keeper’s presence in these areas through the sounds of food preparation, unlocking doors and/or through the visible approach of keepers to the visitor areas or indoor holding. A small portion of the diet was withheld until the bears were brought into holding at 1645. The Animal Care and Use Committee at Cleveland

Metroparks Zoo approved all methods used in this study.

2.2 Study Design

In Experiment One, bears were monitored for one month (June-July) to establish baseline (A) in an ABACA design (Figure 1). Two ten-day feeding enrichment periods

(B and C) were followed by two 11-day carryover periods (A), during which feeding

returned to baseline conditions to test for carryover effects of enrichment, and to allow

any effects of the previous enrichment period to washout before the next enrichment

period began (July-September). The enrichment periods and subsequent carryover periods (BA and CA) were designed to last three full weeks so that both enrichment periods fell on the same days of the week and to control for possible differences in the way different keepers cared for the animals on different days. Experiment Two followed an ADA design, in which a 12-day baseline period was followed by a 30-day habituation test (D; described below), and ended with a 12-day carryover period (September-

November; Figure 1).

In Experiment One, the first feeding-enrichment period (B) consisted of a fixed-

time “work-for-food” program where diets (dog food, produce, and treat items) were

distributed in one of five enrichment items (Figure 2) at 1000 and 1600 daily. Dog food

was the only food item distributed in automatic feeders and produce was the only item

provided in ice blocks. The enrichment items replaced the first and last feeds of the day

from the baseline period. The enrichment was put out on exhibit before the animals were

given outside access in the morning. Bears were called off exhibit for the log feeders to

be refilled in the afternoon, and then immediately let back out onto exhibit. The

automatic feeders, hanging plastic balls, and rotating barrel feeders were able to be pulled

up to the roof of the indoor holding areas, refilled and dropped back down, and the ice

blocks and live fish were tossed in from the visitor areas. Each item was presented for

two consecutive days, which was shown to be the maximum length of time that an item

could be presented to sloth bears before habituation resulted in decreased exploratory

behaviors (Anderson et al., 2010). The second feeding-enrichment period (C) mirrored the conditions of (B), except that feeding enrichment items were presented at two, unpredictable feedings times (randomly assigned to half-hour increments from 1000-

1230 and 1300-1600) that changed daily (Figure 1), instead of the predictable morning and evening times of period B.

Experiment Two consisted of a 30-day habituation test (D) designed based on keeper feedback from the first two enrichment periods in Experiment One. This 30-day

period was made up of three consecutive ten-day cycles, in which each of the five

enrichment items was offered for two consecutive days in the same order as periods (B)

and (C) of Experiment One. In addition, keepers felt that adding flexibility into the time

periods that enrichment was offered would be more practically applicable over the long-

term. Therefore, this period was designed to test if feeding enrichment would continue to

be effective when offered over an extended period of time on a semi-variable schedule, as the keeper could choose to offer the enrichment items as in periods B and C, but at any time from 1000-1230 and from 1300-1600 daily for 30 days.

(A)

(B)

Figure 1. Timeline for experimental design. In Experiment One (A), bears were monitored for one month to establish baseline, after which two 10 day feeding enrichment periods (enrichment periods B and C) were followed by two 11-day carryover periods, during which feeding returned to baseline conditions to test for carryover effects of enrichment. In Experiment Two (B), a 12 day baseline period was followed by a 30 day habituation test (enrichment period D), and ended with a 12 day return to baseline period.

Sunday Monday Tuesday Wednesday Thursday Friday Saturday Baseline Baseline Automatic Automatic Log feeders Log feeders Hanging feeders (A) feeders (A) (B) or live (B) or live plastic balls fish (C)* fish (C)* (D) (Sloth/ (Black/ (Black/ (Sloth/ (Sloth/ (Black/ (Black/ Andean) Brown) Brown) Andean) Andean) Brown) Brown) 1000-1130 1000-1130 1130-1300 1000-1130 1130-1300 1130-1300 1000-1130 1330-1500 1330-1500 1500-1630 1330-1500 1500-1630 1500-1630 1330-1500 Hanging Ice blocks Ice blocks Rotating Rotating Baseline Baseline plastic balls (E) (E) barrel barrel (D) feeders (F) feeders (F) (Sloth/ (Sloth/ (Black/ (Black/ (Sloth/ (Sloth/ (Black/ Andean) Andean) Brown) Brown) Andean) Andean) Brown) 1130-1300 1000-1130 1000-1130 1130-1300 1000-1130 1130-1300 1130-1300 1500-1630 1330-1500 1330-1500 1500-1630 1330-1500 1500-1630 1500-1630

A B

C D

E F

Figure 2. Example enrichment and observation schedule with photos of all enrichment items used in the study. The species observed on a given day and the time they are observed are noted in bold text. Letters in parentheses refer to the corresponding enrichment item images. * During Experiment One, the sloth and Andean bears received log feeders, and the black and brown bears received live fish. During Experiment Two, log feeders replaced live fish for the black bears because they were not interested in the live fish during Experiment One.

2.3 Behavioral Data Collection

A bear-specific ethogram (Table 1) was developed based on published ethograms

for multiple bear species. Behavioral data were recorded 6-7x/week with sloth and

Andean bears observed twice daily for two consecutive days and black and brown bears observed for the next two consecutive days. These days were offset with the two consecutive days that each enrichment item was offered, allowing all individuals to be observed with all five enrichment items during every period (Figure 2). On each observation day, one morning and one afternoon observation was collected, at two alternating times for each session. These times were at either 1000-1130 (hereafter referred to as T1, early morning) and 1330-1500 (T3, early afternoon) or 1130-1300 (T2,

late morning) and 1500-1630 (T4, late afternoon) on alternating days that a given

enrichment item was offered. If the animals needed to be called off for the enrichment

item to be refilled in the afternoon, the observation was paused and resumed when they

were given outside access again.

Observers used instantaneous scan sampling at 1-min intervals (Altmann, 1974), with the species observed alternating every 15 min. Therefore, each species was observed for 45 min during a 1.5-hr observation. Abnormal behaviors were characterized as stereotypies (locomotory, oral or other) or compulsive behaviors (defined by Vickery and Mason (2004) as non-repetitive, apparently functionless, and self-directed, e.g., hair- plucking). At least some behaviors characterized as compulsive using this definition may also be defined as displacement behaviors (Mason, 2006) which, similar to stereotypic behaviors, also seem to arise from a variety of possible underlying drivers including frustrated goal-oriented behaviors, social and other stressors, and deprivation. These

behaviors are often normal behaviors that are out of context (e.g., bar lick, self-directed aggression, and excessive body manipulation) and, if unchecked, may develop into stereotypies.

Table 1. Behavioral ethogram for study

Affiliative behaviors Subject is the instigator of, recipient of, or is mutually engaged in active behavior with a conspecific including play and grooming. Agonistic behaviors Subject is the instigator of, recipient of, or is mutually engaged in active behavior with a conspecific, including paw swipes and bared teeth with audible vocalizations, apparently fighting or chasing. Abnormal Behavior Defined and subdivided into locomotory, oral, or other stereotypies, and compulsive behaviors as detailed in the ethogram developed by Vickerey and Mason (2004). Foraging Subject is consuming, handling, or investigating diet items, browse, or water. Includes foraging or manipulating feeding enrichment. Dig/Scratch Movement of paws against object or ground such that the surface of the object or ground could be disrupted by the action. Often repeated and patterned. Olfactory Subject is sniffing urine or feces and/ or displaying flehmen, please note when flehmen occurs in the notes area. Object Examination Subject is touching, sniffing, or otherwise actively investigating an inanimate, non-food and non-excrement item in its enclosure. Self-directed Behavior Subject is scratching or licking itself, rubbing against an object and/or auto grooming. Elimination Subject is urinating or defecating. Locomoting Subject is propelling body in movement resulting in a transfer of physical position in space that is at least or more than its own body length in distance. Locomoting Alert Subject is moving or bipedal and actively looking around, sniffing, attention is focusing outside the exhibit.

Climbing Animal is locomoting on a climbing structure or other exhibit feature, where simple walking would not suffice. Swimming Aquatic activity, with animal in a pool, where simple walking would not suffice. Stationary/Resting Subject is passive and not engaged in any active behavior. Eyes may be open or closed. Includes sleeping. Stationary Alert Subject is standing or sitting, head raised above the neck and looking around, sniffing, attention is focused outside of the exhibit Other Active Subject is engaging in an active behavior not otherwise defined above. Not Visible The behavior of the subject is not visible or discernible.

Not Visible Tunnel The behavior of the subject is not visible or discernible because they are in the entrance to their night enclosure.

2.4 Statistical Analysis

Experiment One and Experiment Two were analyzed separately. For all analyses

other than behavioral diversity, the behaviors of foraging, dig/scratch, olfactory, and

object examination were combined into a single exploratory behavior category. These behaviors were similar in nature and because some of them were rare, they were combined to improve the power of statistical analysis. Similarly, locomoting, locomoting alert, climbing and swimming were combined into a total locomotion category, stationary alert and locomoting alert were combined into a total alert category, and not visible exhibit and not visible tunnel were combined into a total not visible category. The sloth bears and the male Andean bear were not included in abnormal behavior analyses, because they had the most access to off-exhibit areas and were potentially performing the highest frequencies of abnormal behaviors when not visible, while rarely (<1% of time) observed performing these behaviors on exhibit. All individuals that were included in the

abnormal behavior analyses were only observed performing locomotory stereotypies, so

we were not able to analyze stereotypic behavior by form. The brown bears were the

only species to engage in affiliative behaviors and were the only species analyzed for this

behavior. Andean bears were not included in the analysis of agonistic behaviors, because

they were housed singly for the duration of the study, and did not have any opportunities

to engage in social behaviors. All behaviors other than the total not visible category were

adjusted for the time the bears were visible during the observation. Therefore, all

behaviors are presented as % of time visible on exhibit.

All behaviors except aggression were analyzed using generalized linear mixed

models (GLMMs; PROC GLIMMIX; SAS; SAS Institute, Cary, NC, USA) using a

random intercept, which controls for the assumption that the bears expressed different baseline frequencies of each behavior at the beginning of the study. A negative binomial distribution, log-link function, and variance components covariance structure were used with the “between-within” method for degrees of freedom adjustment in all models. We controlled for inherent variability between individual animals by including them as random factors (subject) in the model. Variables for which we sought to determine effects on each behavior were added to the model as fixed factors (experimental period, time of day, month). Fixed factors considered non-significant at a P>0.10 were removed in a stepwise process unless they contributed to a significantly better model fit. Because experimental period was the main variable related to our hypotheses, it remained as a fixed factor in all models, regardless of significance. To test for habituation in

Experiment Two, the 30-day enrichment period was subdivided into the three ten-day enrichment cycles (the amount of time required to cycle through all five enrichment

items) and included as the main fixed effect in the model. The final models were selected

as the ones with the best fit, measured using the lowest -2 restricted log pseudo-

likelihood estimates. Removal of outliers occurred if they were greater than three

standard deviations (SD) from the mean Pearson residuals value, and if removal led to a significantly better model fit. Post hoc (after final model selection) multiple-comparison analyses were performed on significant factors (Dunnett-Hsu) to examine the specific effects of each experimental period on behavior compared to baseline, the effects of time of day relative to when they were first let out in the morning, and the effects of experimental period by time-of-day interactions. These analyses adjust the significance values based on the number of comparisons. Differences in the effects of the 1st and 2nd

enrichment periods in Experiment One were compared using single-comparison contrast

statements.

Aggressive behaviors were rare in all species (less than 1% of observations in

most periods), and could not be analyzed using GLMMs. Therefore, it was converted

into presence/absence data (0 = aggressive behavior was not observed during the

observation, 1 = aggressive behavior was observed) and analyzed using logistic regression, which models the odds that an animal would have an aggressive interaction in a given observation (PROC LOGISTIC; SAS).

Behavioral diversity scores were calculated using the Shannon-Weiner Index (H), which takes into account the number and frequency of normal behaviors and has previously been used to analyze behavioral diversity in bears (Vickery and Mason, 2004).

Behavioral diversity was analyzed using mixed models (PROC MIXED; SAS). A normal distribution, unstructured covariance structure and the between-within method for

degrees of freedom adjustment were specified. Fixed and random factors tested were the

same as for PROC GLIMMIX. Model building was performed under the maximum

likelihood approximation and non-significant factors were removed in the same step-

down fashion as PROC GLIMMIX unless they led to a better model fit. Cook’s D and

Relative Likelihood Distance tests indicated five outliers that were removed to achieve a

better model fit. The final models were selected as the ones with the best model fit using

the lowest -2 log likelihood estimates and run under restricted maximum likelihood

estimation. Post hoc analyses were performed as described for PROC GLIMMIX.

Results were considered significant at P≤0.05. When adjustments for multiple

comparisons changed the level of significance, both P-values are presented as

(unadjusted, adjusted). Results are presented as least squares mean ± standard error (SE)

with the exception of reporting the overall frequency of behaviors not affected by

experimental period, which are reported as median (interquartile range).

3. Results

3.1 Experiment One

There were differences in the frequency that bears were observed engaging in exploratory, abnormal and self-directed behaviors as well as the amount of time bears were visible on exhibit when enrichment was offered. Experimental period (F4,28=15.99,

P<0.0001), time of day (F3,21=12.47, P<0.0001), and a significant interaction between

these two factors (F12,83=3.33, P<0.001) were associated with changes in the frequency

bears exhibited exploratory behavior. Specifically, bears performed more exploratory

behavior during the two enrichment periods (1st enrichment period: 20.4% ± 4.9%

overall; 2nd enrichment period: 36.2% ± 8.6% overall) compared to baseline (16.0% ±

3.6% overall; Figure 3A-D). This difference occurred mainly in the late afternoon during

the 1st period (P<0.01, P<0.05; Figure 3D). In contrast, during the 2nd enrichment period, the time bears were observed exhibiting exploratory behavior more than doubled over baseline, and performance was distributed throughout the day (T1: P<0.01, P<0.05; T2:

P<0.05, P=0.13; T3: P<0.05, P=0.18; T4: P<0.0001, Figure 3A-D, respectively). The

bears also performed significantly more exploratory behavior during the 2nd enrichment

period compared to the 1st enrichment period (P<0.001). During baseline, exploratory

behavior was highest during the morning observations and decreased in the afternoon (T3

vs T1: P<0.01; T4 vs T1: P<0.01). In contrast during the 1st fixed-time enrichment

period, exploratory behavior only decreased during the times when enrichment was not

offered to the bears (T2 vs T1: P<0.01; T3 vs. T1: P<0.001). Finally when enrichment

was offered at variable times during the 2nd enrichment period, exploratory behavior was

more consistent throughout the day, with a dip in frequency occurring only during the

early afternoon observation time (P<0.01).

Changes in the frequency of abnormal behavior the bears exhibited were

associated with experimental period (F4,16=5.29, P<0.01) and time of day (F3,21=17.60,

P<0.0001). Both fixed-time (9.1% ± 2.8%, P<0.05, P=0.07) and variable-schedule (9.0%

± 2.9%, P<0.05, P=0.09) enrichment were associated with decreased abnormal behavior

compared to baseline (16.5% ± 4.7%), and they were not significantly different from each

other (Figure 4A). The bears performed the lowest amount of abnormal behavior when

first let out in the morning and performance remained low for the late morning before

46 significantly increasing during all experimental periods (T3 vs T1: P<0.01; T4 vs T1:

P<0.001).

Figure 3. Differences in exploratory behavior between B: baseline, E1: fixed-time enrichment, C1: 1st carryover, E2: variable-time enrichment and C2: 2nd carryover periods in Experiment One, paneled by observation time. Bold lines within the box are the mean percent of time visible and whiskers represent the interquartile range in A) T1:1000-1130, B) T2:1130-1300, C) T3:1330-1500 and D) T4:1500-1630 under. * = significant before adjustment, ** = significant after Dunnet’s adjustment for multiple comparisons (P<0.05).

There was also an association between experimental period and self-directed

behavior (F4,28=3.34, P<0.05). The bears performed the most self-directed behaviors during baseline, and performance decreased during the subsequent 1st (P<0.01) and 2nd

(P<0.01) enrichment periods, and their respective carryover periods (P<0.01, P<0.05;

P<0.01, P<0.05, Figure 4B).

The amount of time the bears were visible in their enclosure also varied by

st experimental period (F4,28=5.53, P<0.01). Bears were more visible during the 1 (18.1 ±

7.4% of observation not visible, P<0.001) and 2nd (11.2 ± 4.6% of observation not

visible, P<0.05, P=0.14) enrichment periods compared to baseline (26.7 ± 10.4% of observation not visible), although they were significantly less visible when presented with enrichment on a variable schedule rather that at fixed times (P<0.05). This effect was not seen in the carryover periods (Figure 4C).

There were no differences in the amount of time bears exhibited aggression, affiliative, resting, alert, locomotion or eliminatory behaviors, or with behavioral diversity in relation to the experimental period. Of these behaviors, the bears were most frequently observed resting [23.3% (2.7%-57.1%)], followed by locomoting [8.3%

(2.2%-16.3%)], and were observed engaging in alert and affiliative behaviors at lower frequencies, [4.7% (0.0%-13.6%) and 4.6% (0.0%-16.7%), respectively], with engagement in aggression and eliminatory behaviors constituting less than 1% of daily activity when visible throughout the experiment.

Figure 4. Differences in abnormal behavior, self-directed behavior, and time not visible between B: baseline, E1: fixed-time enrichment, C1: 1st carryover, E2: variable-time enrichment and C2: 2nd carryover periods in Experiment One. Bold lines within the box are the mean percent of time visible bears spent exhibiting A) abnormal and B) self-directed behavior and C) time not visible. Whiskers represent the interquartile range * = significant before adjustment, ** = significant after Dunnet’s adjustment for multiple comparisons.

3.2 Experiment Two

Similar to Experiment One, variations in the time bears performed exploratory behavior were associated with experimental period (F2,14=43.35, P<0.0001), time of day

(F3,21=17.10, P<0.0001), and an experimental period by time of day interaction

(F6,42=3.67, P<0.01). Overall, bears exhibited an increase in exploratory behavior from

12.1 ± 2.2% during baseline to 32.0 ± 5.3% during the enrichment period. Within each observation time period (T1-T4) exploratory behavior increased in the experimental period compared to the same time during baseline (T1: P<0.001; T2: P<0.01; T3:

P<0.0001; T4: P<0.0001; Figure 5A-D, respectively). Although bears continued to exhibit exploratory behaviors more frequently in the carryover period relative to baseline, this effect was only seen during the early morning observation (P<0.001; Figure 5A) after bears were first let out and fed consistent with baseline conditions. During baseline, exploratory behaviors were highest when bears were first let out and fed in the morning but decreased in the afternoon (T3 vs. T1: P<0.05; T4 vs. T1: P<0.05, P=0.06). In contrast, during the 30-day enrichment period, when enrichment was offered on a semi- variable schedule, exploratory behavior remained more consistent throughout the day, with a dip in frequency occurring only during the late morning observation time

(P<0.05). This effect was no longer seen when the bears returned to baseline feeding conditions in the carryover period. There was no change in exploratory behavior as bears progressed through the three successive ten-day cycles in which enrichment was offered.

Experimental period (F2,8=3.97, P=0.06), time of day (F3,12=52.62, P<0.0001), and a significant interaction between the two (F6,24=17.60, P<0.01) were associated with changes in the frequency of time bears were observed performing abnormal behaviors.

Overall bears exhibited abnormal behaviors for 16.6 ± 4.2% of time during baseline

compared to 11.4 ± 2.8% during the enrichment period and 9.6 ± 2.8% during the

carryover period. Bears exhibited fewer abnormal behaviors during the late morning for

both the enrichment (P<0.01, Figure 5F) and the 12-day carryover (P<0.001, Figure 5F)

periods compared to baseline. During baseline, the amount of time bears spent

performing abnormal behavior increased throughout the day, starting at the 11:30 (late

morning) observation time. The most significant increases were seen in the late

afternoon (T2 vs. T1: P<0.01; T3 vs. T1: P<0.001; T4 vs. T1: P<0.0001) when compared

to the time bears were first let out in the morning. This increase in abnormal behavior

was delayed until the afternoon when the bears were enriched on a semi-variable schedule (T3 and T4 vs. T1: P<0.0001) and during the carryover period after bears

returned to baseline conditions (T3 vs. T1: P<0.01, P<0.05; T4 vs. T1: P<0.0001,

P<0.001). Furthermore, bears performed less abnormal behavior in the late morning

during the carryover period (T2 vs T1: P<0.05). There was no change in abnormal

behavior as bears progressed through the three ten-day periods in which we cycled

through the five enrichment items.

Experimental period (F2,14=3.12, P=0.08), time of day (F3,21=26.51, P<0.0001),

and an experimental period by time of day interaction (F6,42=3.01, P<0.05) were all

associated with changes in the amount of time bears were observed resting. Overall bears rested 26.2 ± 4.4%, 23.3 ± 3.7% and 31.4 ± 5.6% of time during the baseline, enrichment and carryover periods, respectively. Compared to baseline, the bears rested less frequently during the early afternoon when enriched (P=0.03, P=0.05, Figure 5K), an effect also seen in the carryover period but only during the early morning observation

time (P<0.05, Figure 5I). The amount of time bears spent resting was consistent in the first three time periods of the day before decreasing in the late afternoon in both the baseline and enrichment period (T4 vs. T1: P<0.0001 for both periods). In contrast, the bears rested significantly more in the middle two time periods of the day compared to early morning (T2 vs. T1: P<0.01, T3 vs T1: P<0.05, P=0.13) during the carryover period. When looking only at the 30-day period that bears were enriched, they rested for

18.08 ± 3.4% of time visible for the first ten days they were offered enrichments, and resting subsequently increased to 26.0 ± 4.8% and 27.4 ± 5.2% of time visible for the two subsequent ten-day periods (P<0.05, P=0.08 and P<0.05, respectively, compared to the first 10 days).

Figure 5. Differences in exploratory (A-D), abnormal (E-H) and stationary/rest (I-L) behaviors between the B: baseline, E: semi-variable time enrichment and C: carryover periods in Experiment Two, paneled by observation time. Bold lines within the box are the mean percent of time visible bears spent exhibiting, exploratory, abnormal, and stationary/rest behaviors (columns from left to right) and whiskers represent the interquartile range. Each behavior is paneled by observation time: T1:1000-1130 (Panels A,E,I), T2:1130- 1300 (panels B,F,J), T3:1330-1500 (Panels (C,G,K) ) and T4:1500-1630. * = significant before adjustment, ** = significant after adjustment for post hoc comparisons

Differences in the amount of behavioral diversity that bears exhibited were

associated with experimental period (F2,14=6.85, P<0.01). Bears showed a greater

diversity of behaviors when enriched, compared to baseline (P<0.05, P=0.07, Figure 6),

an effect not seen during the carryover period. There was no change in behavioral

diversity as the enrichment period progressed through the three successive ten-day

enrichment cycles, although behavioral diversity did not increase significantly until after

the first ten-day cycle when compared to baseline (P<0.01, P<0.05).

Figure 6. Differences in Shannon-Weiner diversity indices between B: baseline, E: semi-variable time enrichment schedule and C: carryover period in Experiment Two. Bold lines within the box are the mean Shannon-Weiner Diversity Index scores under. Whiskers represent the interquartile range. * =significant before adjustment, ** = significant after adjustment for post hoc comparisons.

Neither the frequency of time bears spent performing alert, aggression, affiliative,

self-directed, locomotion, nor eliminatory behaviors, nor time spent visible were associated with the experimental period. The time bears spent exhibiting locomotion behavior was the most frequent [6.8% (2.2%-16.7%)], followed by performance of alert and affiliative behaviors [4.7% (0.0%-15.8%) and 2.9% (0.0%-9.2%), respectively], with aggression, self-directed and eliminatory behaviors observed less than 1% of the time

bears were visible throughout the experiment. The bears were not visible for 6.7%

(0.0%-73.3%) of the observations.

4. Discussion

We aimed to investigate the effects of a fixed vs. variable time “work-for-food”

enrichment program on behavioral measures of welfare in bears and examine whether

habituation to an enrichment program would occur if sustained for a 30-day period. As

hypothesized, our results from Experiment One demonstrate that feeding enrichment

increases exploratory behaviors and visibility, and decreases abnormal behaviors.

Unexpectedly, self-directed behavior also decreased. Although a variable feeding schedule did not decrease the magnitude of change in time engaged in abnormal behaviors or time visible relative to baseline, it led to significant increases in exploratory behaviors distributed more evenly throughout the day compared to baseline. Finally, there appeared to be no habituation when the feeding enrichment program was sustained for a 30-day period on a semi-variable feeding schedule, with increases in exploratory behaviors and decreases in abnormal behaviors consistent with Experiment One.

Feeding enrichment increased exploratory behavior in this study, agreeing with

the finding from a meta-analysis by Swaisgood and Shepherdson (2005) that

environmental enrichment increased natural, active behaviors in 74% of studies. Our

results also support a number of experimental studies where feeding enrichment resulted

in increased exploratory and food-related behaviors in multiple species, including

spectacled bears (Fischbacher and Schmid 1999), sun bears (Schneider, Nogge, and

Kolter 2014) and red foxes (Kistler et al. 2009). Although increased feeding frequency

combined with an unpredictable feeding schedule increased foraging/exploratory

behavior in one black bear (Carlstead et al., 1991), this is the first experiment to

demonstrate that an unpredictable feeding schedule stimulates increases in the magnitude

and temporal distribution of exploratory behaviors in bears. Exploratory behavior

increased from approximately 16% of time visible to approximately 36% of time visible

when the feeding schedule was variable in Experiments One, which is similar to 40% of time that bears spend foraging in the wild (Clubb and Mason, 2007). However, our observations were only conducted during daytime operating hours. Therefore, it may be pertinent to look at the effects of increasing the number of feeding enrichment presentations throughout the 24-hour day, and whether there is variation in the effectiveness of feeding enrichment when presented during twilight or at night.

Feeding enrichment decreased abnormal behaviors in both enrichment periods of

Experiment One, supporting our hypothesis. Our results support findings by Swaisgood and Shepherdson (2005) and Shyne (2006), who respectively found that enrichment was associated with statistically significant reduced stereotypic behaviors in 53% of studies, and that 90% of enrichment studies have effect sizes in the expected direction..

Abnormal behaviors were reduced from approximately 17% to 9% of time visible, representing a shift from above to below the 12.4% of the time that bears are reported to

spend stereotypic pacing on average (Swaisgood and Shepherdson, 2006). Because

feeding enrichment reduced abnormal behaviors in the bears in our study, it is likely that

their abnormal behaviors were at least partly motivated by frustration from lack of

foraging opportunities. However, adding temporal unpredictability failed to increase the

magnitude of this effect, in contrast to the finding that unpredictable feeding times were

associated with less stereotypic behavior in cheetahs (Quirke et al., 2012). This may be

explained by the management of the black and brown bears under baseline conditions.

Because these species were scatter fed their regular diet items on a variable schedule

between 2-4x in the middle of the day under all experimental periods, varying the time

that the additional feeding enrichment was offered may not have added enough variability

to their already semi-variable schedule to warrant extra benefits, and therefore no

increased effect was seen overall. Additionally, Carlstead and Seidensticker (1991) found that although a combination of increased feeding frequency and an unpredictable feeding schedule from an automatic feeder increased foraging/exploratory behaviors in a black bear, it had no effect on abnormal behaviors. Therefore, an unpredictable feeding schedule may not reduce abnormal behaviors in bears.

Alternatively, multiple underlying drivers may be behind the abnormal behavior of the bears in our study that the unpredictable feeding schedule failed to address.

Fischbacher and Schmid (1999) found that feeding enrichment did not decrease

stereotypic behaviors in Andean bears outside of increased foraging time immediately

after morning food presentation. The authors hypothesized that feeding enrichment likely

failed to address the underlying frustrations in these individuals, as performance of

stereotypic bouts were closely associated with a lack of appropriate resting spots for the

older female and frustrated social behaviors in the male. Rog et al. (in review) observed that frustrated escape attempts and incompatibilities in the social group seemed to be the underlying drivers behind stereotypic pacing bouts in a female sun bear. After the two females were separated and the focal female was given off-exhibit access, pacing ceased with the exception of short periods of time when the females was locked out while the keepers cleaned the indoor holding area. We saw a similar pattern of behavior in the

sloth bears in our study, as they were only observed performing locomotory stereotypies

when their access to indoor holding was closed for cleaning. However, because sloth

bears may have performed stereotypic behaviors in the off-exhibit areas where their behavior was not visible from the visitor viewing area, they were excluded from the abnormal behavior analysis. Video monitoring of the bears’ behavior in these areas would have allowed for a more thorough analysis of not only abnormal behaviors, but also the overall activity budget during normal operating hours instead of being adjusted for time visible.

Finally, it is also possible that the stereotypic behaviors exhibited by the bears in our study were anticipatory behaviors, not necessarily exhibited in frustration from thwarted goal-oriented behaviors but in anticipation of a positive experience such as the presentation of food and/or feeding enrichment, or gaining access to the indoor holding area. These behaviors may be similar in form to stereotypic behavior (e.g., pacing).

However, although animals engaged in stereotypic pacing are characterized as rigid and have invariant bouts that last for at least three repetitions [characteristics validated by

Cless et al. (in press)], animals exhibiting anticipatory pacing are described as “looking for a distraction” (Watters, 2014) and may frequently break their pacing bouts to check if the door to indoor holding is open, or to determine if they can detect the presence of a caretaker. Although sometimes thought to be an indicator of positive welfare (the animals must experience something positive in order to anticipate it), they may also indicate that the individual is receiving the positive experience at a low frequency, as, for example, an underfed bear would be expected to have vigorous and lengthy bouts of anticipatory behavior (Watters, 2014). Therefore, even if the bears in this study had a

positive affective state while performing anticipatory behaviors, the reduction in

anticipatory behaviors would likely indicate that they were receiving more experiences

that are positive and thus their sensitivity to it was lower. The overall interpretation

would still indicate a shift towards increased positive welfare.

The bears performed fewer self-directed behaviors in response to feeding

enrichment during Experiment One, in contrast to findings in the literature. For

examples, Renner and Lussier (2002) reported no difference in the amount of grooming, or body/face rubbing exhibited by spectacled bears in response to enrichment and Liu et

al. (2003) found that giant pandas in large, naturalistic enclosures performed similar

amounts of grooming as those in small, more barren enclosures. Because self-directed

behaviors seemed to be unusually high during the baseline of Experiment One compared

to all other experimental periods throughout the study (including those of Experiment

Two), it may have been a seasonal difference. This hypothesis is supported by an observation on a single black bear by Carlstead and Seidensticker (1991) who observed him rub his body against the wall of his enclosure during the early summer (May-June),

but not during the late summer and fall (July-November), correlating with species-typical scent marking behavior of wild black bears during the breeding season (Carlstead and

Seidensticker, 1991; Spady et al., 2007). Because both the tropical and temperate species of bears included in our study are known to show seasonal reproductive patterns when housed at temperate latitudes (Spady et al., 2007), the bears may have been performing more seasonally relevant scent marking behaviors (included under self-directed behaviors) during the baseline period of the first study.

Although not necessarily an indicator of welfare, the bears were more visible in

both enrichment periods compared to baseline in Experiment One. However, contrary to

our expectations, they were more visible during the fixed-time enrichment period

compared to the unpredictable feeding schedule. Because animals on a fixed schedule

easily predict feeding times (Vickery and Mason, 2004), they may have been out in

public view, where many of the enrichment items were anchored, in anticipation of the

items being refilled with food. The effects of feeding enrichment on visibility in the

literature are variable. Although Bashaw et al. (2003) found that providing bones to lions

(Panthera leo) led to non-significant increases in visibility during and two days post-

enrichment, Mcphee (2002) observed increased hiding behavior when large felids were

carcass fed. It is possible that we saw consistent increases in visibility during Experiment

One because many of the enrichment items were anchored in places that were visible to

the public, which in turn may have reinforced the bears for being in those spaces.

Similarly, feeding enrichment anchored to climbing structure enrichment resulted in

greater visibility in a male spectacled bear, although visibility in the female decreased

(Renner and Lussier, 2002).

In Experiment Two, no habituation was seen during the 30-day sustained

enrichment offering for any of the behaviors except rest. Our study was designed to

avoid habituation to the feeding enrichment program, based on the findings that any one

enrichment item should not be offered for more than two consecutive days, and should be

intermittently presented (Anderson et al., 2010). Carlstead, Seidensticker, and Baldwin

(1991) also found that bears showed renewed interest in logs filled with honey, similar to

first presentation, when intermittently filled with honey. Additionally, a semi-variable

feeding schedule may also have prevented habituation, as (Schneider et al., 2014)

observed no decreases in foraging behavior over 12 days when spatial unpredictability

was added to their enrichment program.

In contrast to Experiment One where we observed no changes in resting behavior,

we found that while there was little difference between the overall amounts bears rested

during the enrichment period (23%) compared to the baseline period (26%) they rested

significantly less during the first afternoon observation of the enrichment period

compared to baseline in Experiment Two. This finding is consistent with observations that enrichment decreased resting in spectacled bears (Renner and Lussier, 2002).

However, within the 30-day enrichment period, the bears rested less compared to baseline only during the first ten days enrichment was offered, and inactivity increased throughout

the last 20 days. Bears became increasingly inactive into the carryover period, during

which time bears rested for 31% of time visible, although they rested less than baseline

during the first morning period. This increase was likely a result of seasonal differences that began to take place after the first ten day of the enrichment period, as Experiment

Two approached the time of hibernation in temperate latitudes in North America. This change in behavior was most easily observed in one of the black bears, who went six days during the late enrichment and early post-enrichment period without coming out onto exhibit or eating (personal observation). This may have also been the reason that enrichment failed to increase visibility in Experiment Two, as there was a trend towards time not visible consistent with the trend in resting. Furthermore, many of the preferred resting spots for the bears in this study were in areas not visible to the public, as they offered the most shade and shelter from the weather (personal observation).

Although bears in the wild are generally thought of as crepuscular, they may shift

their activity based on resource conditions (Garshelis, 2004). It seems that the bears in

this study also modulated their activity based on when food would be available, resting

less and demonstrating more exploratory behaviors during the observation periods in

which they either received, or anticipated receiving enrichment. When the bears stopped

receiving enrichment during the middle two observations of carryover period, they rested

significantly more than during the first morning and last afternoon observations,

consistent with a crepuscular activity budget.

An additional contrast with Experiment One was an observed increase in

behavioral diversity during Experiment Two. Variable feeding schedules have been shown to increase behavioral diversity in red foxes (Kistler et al., 2009) and cheetahs

(Quirke and O’Riordan 2011), and behavioral diversity was increased in the three studies

that reported this measure in Swaisgood's and Shepherdson's(2005) meta-analysis.

Therefore, this contrast may demonstrate that offering enrichment for a sustained period

may actually increase the effectiveness of enrichment with regards to behavioral

diversity. In support of this, we found that although behavioral diversity was not

significantly different across the three ten-day cycles of the 30-day enrichment period,

behavioral diversity did not increase during the enrichment period relative to baseline until after the first ten days that enrichment was offered.

Feeding enrichment was consistently associated with higher levels of exploratory

behavior and lower levels of abnormal behavior in both experiments, indicating several

welfare benefits. This enrichment program effectively increased behavioral signs of

positive welfare by creating an environment in which exploratory behavior had increased

functional significance (expressing these behaviors increased the amount of food they

were able to consume). Furthermore, adding temporal unpredictability, through the

variable feeding schedule in Experiment One and the semi-variable feeding schedule in

Experiment Two, benefited the feeding enrichment program by increasing the magnitude

and distribution of exploratory behaviors. Finally, the consistent decreases in abnormal

behavior demonstrate that feeding enrichment reduced behavioral indicators of negative

welfare, an aspect that did not seem to be altered by temporal unpredictability.

5. Conclusions

Because feeding enrichment is an effective and efficient way to both increase

behavioral indicators of positive welfare and decrease behavioral indicators of negative

welfare, we suggest that replacing more conventional feeding methods with feeding

enrichment is a valuable method for increasing well-being in zoo-housed bears. We also suggest that a schedule incorporating variable feeding time can enhance a “work-for- food” enrichment program, while a schedule implementing consecutive enrichment offerings, but intermittent presentation of specific enrichment items can help prevent habituation to enrichment. Although this enrichment program stimulated the bears to perform increased exploratory behaviors and decreased abnormal behaviors, there are a number of future steps that could be taken to promote positive affective states in these bears.

Given that bears are typically crepuscular (Garshelis, 2004), a future study might look at the differential effects of enrichment offered beyond the typical, diurnal work day of keepers. Observations that expand into the twilight and night hours may uncover that

feeding enrichment is more biologically relevant and effective when offered during those

hours.

It was previously demonstrated that enrichment programs that are in place for

months or years are more effective at reducing stereotypic behavior than those in place

for days or weeks (Swaisgood and Shepherdson, 2006). A future study could examine

the effects of this program for a longer period, but because this “work-for-food” program

was shown to be effective without habituation over a 30-day period, the program would

best be incorporated into the daily husbandry of these individuals, rather than being

considered enrichment. In this way, studies designed to further improve the welfare of

these individuals using enrichment would consider this program as part of the baseline

conditions, and try to enhance the bears wellbeing using additional measure to address

other possible underlying stressors and motivations, e.g., by giving the bears access to

off-exhibit areas, or by putting in climbing/shade structures. Enrichment deemed

effective could continue to be incorporated into their normal husbandry, and new

interventions could be systematically evaluated in a stepwise process, until abnormal

behaviors are extinguished and activity levels approach those of wild bears.

Although the current Animal Care Manual for polar bears recommends feeding

enrichment (scatter feeding, a variable time schedule, and food presented in enrichment

items) as part of a balanced diet and as a method to reduce stereotypic behavior (AZA

Bear TAG, 2009), neither the AZA accreditation standards (AZA, 2013) nor the USDA

(USDA, 2013) currently requires that bears be fed in this way. A multi-institutional study examining the welfare effects of this enrichment program would increase the generalizability of our findings and, if they were found to have external validity, could be

65 an important next step suggesting that giving bears the opportunity to work for their food should be a requirement beyond the provision of environmental enrichment.

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