Establishing a Link Between Personality and Social Rank in a Group of Bottlenose Dolphins (Tursiops Truncatus)

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Master's Theses

Summer 8-2016

Establishing a Link Between Personality and Social Rank in a Group of Bottlenose Dolphins (Tursiops truncatus)

Erin Elizabeth Frick University of Southern Mississippi

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Recommended Citation Frick, Erin Elizabeth, "Establishing a Link Between Personality and Social Rank in a Group of Bottlenose Dolphins (Tursiops truncatus)" (2016). Master's Theses. 186. https://aquila.usm.edu/masters_theses/186

This Masters Thesis is brought to you for free and open access by The Aquila Digital Community. It has been accepted for inclusion in Master's Theses by an authorized administrator of The Aquila Digital Community. For more information, please contact [email protected]. ESTABLISHING A LINK BETWEEN PERSONALITY AND SOCIAL RANK IN A

GROUP OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

Erin Elizabeth Frick

A Thesis Submitted to the Graduate School and the Department of Psychology at The University of Southern Mississippi in Partial Fulfillment of the Requirements for the Degree of Master of Arts

Dr. Stanley A. Kuczaj Thesis Director, Professor, Psychology

Approved:

______Dr. David Echevarria, Committee Chair Associate Professor, Psychology

______Dr. Donald Sacco, Committee Member Assistant Professor, Psychology

______Dr. Holli Eskelinen, Committee Member Assistant Director of Research, Dolphins Plus

______Dr. Karen S. Coats Dean of the Graduate School

August 2016

Erin Elizabeth Frick

2016

Published by the Graduate School

ABSTRACT

ESTABLISING A LINK BETWEEN PERSONALITY AND SOCIAL RANK IN A

GROUP OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS)

by Erin Elizabeth Frick

August 2016

Bottlenose dolphins (Tursiops truncatus) have been documented to possess personality traits that remain consistent over time (Highfill & Kuczaj, 2007) and across contexts (Kuczaj, Highfill, & Byerly, 2012). Such individual differences are thought to play an important role in various social contexts such as hierarchical dominance (Highfill

& Kuczaj, 2010). The present study investigated the relationship between personality and social rank within a captive group of bottlenose dolphins housed at the Roatan Institute for Marine Science (RIMS). Social rank was established using questionnaires distributed to the RIMS experienced staff. Personality traits were derived from behavioral coding using context-specific correlational matrices. The traits were then correlated to each dolphin’s social rank position. The results suggest that a relationship between individual personality and social status is present, but complex. Traits that emerged exhibited sex- differences. Of the 12 factors found for the males, sexual (DID), contact seeking (DIO), and camaraderie (DID) were significantly related to social rank. For the females, only factors playful (DIO) and evasive (DIH) were significantly related to social rank.

Individuals ranked at both extremes of the hierarchy (highest and lowest) seem to exhibit a more correlative relationship between personality and social status. However, other factors appear to play an important role in this relationship for middle-ranked dolphins.

These results suggest that factors such as age, strength of associations between

individuals, maternal style, and interactions between the male and female hierarchies all influence how personality is expressed in different contexts.

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ACKNOWLEDGMENTS

I would like to thank my committee members: David Echevarria, for his mentorship and unyielding support in research and life; Holli Eskelinen, for her advice, continued guidance, and invaluable feedback; and Donald Sacco, for his keen eye for parsimony. This project would not have been possible without help from the Roatan

Institute for Marine Sciences staff and trainers for allowing us to collect the data, and

Kendal Smith for her time and efforts coding reliability.

I would like to thank my lab colleagues, friends, and family; I could not have made it through this process without your support. Special thanks to Kelley Winship,

Audra Ames, and Kelsey Moreno for their work on feedback and edits, and Chris

Lustgraaf, for his statistical assistance and constant encouragement.

Finally, I would like to thank and honor my mentor, Dr. Stan Kuczaj, who passed away before the completion of this process. I will be forever grateful for your unyielding support and the work you contributed to this project. You were not only my mentor, but also a friend, and I hope my continued research in this field will carry on part of your legacy, along with all of us impacted by our time spent working with you.

TABLE OF CONTENTS

ABSTRACT ...... ii

ACKNOWLEDGMENTS ...... iv

LIST OF TABLES ...... vii

LIST OF ILLUSTRATIONS ...... viii

CHAPTER I – INTRODUCTION ...... 1

Research in Animal Personality ...... 1

Current Study ...... 13

CHAPTER II – METHODS ...... 16

Subjects and Facility ...... 16

Data Collection ...... 17

Data Analysis ...... 19

CHAPTER III - RESULTS ...... 25

Social Rank ...... 25

Personality...... 25

Personality and Social Rank ...... 30

Males ...... 30

Females ...... 31

Agentic and Communal Factors ...... 32

CHAPTER IV – DISCUSSION...... 35

Relationship between Personality and Social Rank ...... 35

Sex-Differences...... 44

Limitations ...... 47

Future Directions ...... 49

Conclusions ...... 50

APPENDIX A – Ethogram ...... 52

APPENDIX B - Correlation Matrix Tables ...... 55

APPENDIX C - Institutional Animal Care and Use Committee Notice of Committee

Action ...... 60

REFERENCES ...... 61

LIST OF TABLES

Table 1 Demographic Information for RIMS dolphins ...... 17

Table 2 Behaviors in each Context Retained for Analysis for Males and Females ...... 21

Table 3 Composite Personality Traits for Male Dolphins ...... 27

Table 4 Composite Personality Traits for Female Dolphins ...... 27

Table 5 Personality Profile for the Male Dolphins ...... 28

Table 6 Personality Profile for the Female Dolphins...... 29

Table A1. Operational Definitions of Behaviors Coded ...... 52

Table A2. Operational Definitions of Contexts ...... 54

Table A1. Spearman Rank Correlation Matrix for Male DID Coded Items ...... 55

Table A2. Spearman’s Rank Correlation Matrix for Female (DID) Coded Items ...... 56

Table A3. Spearman’s Rank Correlation Matrix for Male (DIO) Coded Items ...... 57

Table A4. Spearman’s Rank Correlation Matrix for Female (DIO) Coded Items ...... 57

Table A5. Spearman’s Rank Correlation Matrix for Male (DIH) Coded Items ...... 58

Table A6. Spearman’s Rank Correlation Matrix for Female (DIH) Coded Items ...... 58

Table A7. Spearman’s Rank Correlation Matrix for Female (DIA) Coded Items ...... 59

vii

LIST OF ILLUSTRATIONS

Figure 1. Aerial photograph of Roatan Institute for Marine Science dolphin enclosure. 16

Figure 2. Social rank for the (A) males and (B) female dolphins at RIMS...... 25

Figure 3. Personality traits significantly correlated to social rank in male dolphins...... 30

Figure 4. Personality trait scores significantly related to social rank for females...... 31

Figure 5. Agentic and communal scores in the male hierarchy...... 33

Figure 6. Agentic and communal scores in the female hierarchy...... 33

Figure 7. Mean agentic scores...... 34

Figure 8. Mean communal scores...... 34

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CHAPTER I – INTRODUCTION

Research in Animal Personality

Personality can manifest in a wide range of contexts and influence many aspects of an animal’s life history. Yet, defining personality in non-human animals has been a difficult topic to agree upon in much of the previous literature. Gosling (2008) offers a fairly well- accepted consensus for personality in non–human animals, defined as characteristics of individuals that describe and account for temporally stable patterns of affect, cognition and behavior. Research in mammalian and non–mammalian species has demonstrated that individuals of a similar age class and gender often behave differently when they are in similar situations (Gosling & John, 1999; Vazire & Gosling, 2004).

Individual differences (i.e., variation in behavior from one animal to another; Locurto,

2007) persist over a period of time and are considered characteristics of personality.

Individual differences were once thought to be unique to humans, but recent evidence has suggested individual differences in personality can be found in non–human animals (e.g.,

Buirski, Plutchik, & Kellerman, 1978; Gosling, 2001; Locurto, 2007). These qualities are thought to arise from genetic differences (Weiss, King, & Figueredo, 2000; Weiss et al.,

2009), various forms of environmental exposure (King, Weiss, & Farmer, 2005), social interactions (Krause, James, & Croft, 2010), context of the behavior (Koski, 2011;

Kuczaj et al., 2012), and more recently, to have hierarchical structure (Latzman, Hopkins,

Keebaugh, & Young, 2014). However, determining when individual differences become established personality traits has not been defined clearly, likely due to the difficulty of obtaining empirical evidence, as well as the inability of a non-human animal to explicitly convey information to the researcher. Thus, behaviors and contexts in which target

behaviors are being displayed are utilized to assess animal personality and individual differences (Dawkins, 2006; Gosling, 2001; Highfill & Kuczaj, 2007; Horback, Miller, &

Kuczaj, 2013; Krause et al., 2010; Kuczaj et al., 2012).

Nonetheless, personality traits have been identified in a number of animal species, including Garnett’s bush babies (Otolemur garnettii; Highfill, 2008), capuchin monkeys

(Sapajus apella; Morton et al., 2013), chimpanzees (Pan troglydytes; King & Figueredo,

1997; King et al., 2005; Weiss et al., 2009), dogs (Canis lupus familiaris; Gosling &

John, 1999; Gosling, Kwan, & John, 2003; Svartberg & Forkman, 2002), bottlenose dolphins (Tursiops truncatus; Highfill & Kuczaj, 2007; Kuczaj et al., 2012), African elephants (Loxodonta africana; Horback et al., 2013), Asian elephants (Elephas maximus; Highfill, Fad, Makecha, & Kuczaj, 2013; Yasui et al., 2013), hyenas (Crocuta crocuta; Gosling, 1998; Watts, Blankenship, Dawes, & Holekamp, 2010), golden snub- nosed monkeys (Rhinopithecus roxellana; Jin, Su, Tao, Guo, & Yu, 2013), orangutans

(Pongo pygmaeus; abelii; Weiss, King, & Perkins, 2006) piglets (Sus scrofa domesticus;

Forkmann, Furuhaug, & Jensen, 1995), rhesus macaques (Macaca mulatta; Capitianio,

1999; Capitianio & Widaman, 2005), black rhinoceros (Diceros bicornis; Carlstead,

Mellen, & Kleiman, 1999), rainbow trout (Oncorhynchus mykiss; Frost, Winrow-Giffen,

Ashley, & Sneddon, 2007), snow leopards (Uncia uncia; Gartner & Powell, 2012), zebrafish (Danio rerio; Martins & Bhat, 2014; Toms & Echevarria, 2014;), octopus

(Octopus rubescens; Mather & Anderson, 1993), and dumpling squids (Euprymna tasmanica; Sinn & Moltschaniwskyj, 2005).

Animal personality is predominantly assessed through observable and measurable characteristics of individuals that describe consistent patterns of specific traits,

contemplative type behavior, and sustained states of behavioral response (Locurto, 2007).

The two principal methods utilized to assess personality in animals are rating and coding

(Vazire & Gosling, 2004). The rating method consists of experienced human observers judging an animal’s behavioral tendencies across different environmental conditions and contexts (Highfill, Hanbury, Kristiansen, Kuczaj, & Watson, 2010). Each observer is provided with an exhaustive questionnaire or list of behavioral traits. Observers systematically and objectively rate (typically a Likert-type scale) each individual animal for particular traits (Freeman et al., 2013; Highfill & Kuczaj 2007; King & Figueredo,

1997; Kuczaj et al., 2012). Multiple ratings are acquired from several human raters for each animal to gain an objective overview. Ideally, raters have similar previous experience ( > 1 year) with the animals as well as have interactions with the animals in similar, yet diverse, contexts. This minimizes the potential for subjective biases during data collection and interpretation (Highfill et al., 2010). Scores are then collated and analyzed for discrete traits that are scaled repeatedly and consistently over time to comprise a picture of each individual animal’s personality profile (Dutton, Clark, &

Dickins, 1997).

The coding method assesses animal behavior directly within the key dimensions of personality by recording naturally occurring behaviors (ethological coding) across different dimensions and clustering those behaviors into emergent traits (Horback et al.,

2013; Koski, 2011; Uher & Asendorf, 2008). Individual differences arise from the scoring of a specific trait. Use of the coding method is considered to capture more species-specific components of personality (Freeman et al., 2013; Highfill et al., 2010;

Horback et al., 2013; Koski, 2011). Analyses associated with the coding methodology

range depending upon how the data is collected. Uher and Asendorf (2008) coded behaviors in experimental testing conditions aimed at specific components of personality

(i.e., curiosity was tested in a novel food approach paradigm) and were aggregated using

Cronbach’s α and Pearson’s r correlation. Horback and colleagues (2013) coded 18 behaviors of African elephants in a natural captive setting and grouped behaviors into emergent trait groups using Spearman rank order correlation matrices.

While coding provides a personality trait assessment comprised from an individual animal’s behaviors across time and context, the rating method scores behavioral tendencies based upon previous background knowledge of the animal. Though there is no obvious methodological preference between rating and coding in personality research (Highfill et al., 2010), some researchers argue that the combined use of both methods yields more reliable and valid data, and provides more information pertaining to individual differences (Carlstead et al., 1999; Gosling & Vazire, 2004). Typically the use of both methods is rare due to how time consuming coding of naturally occurring behaviors can be, and how difficult it is finding a sufficient number of knowledgeable raters with similar prior experience with the study subjects (Highfill et al., 2010).

However, this psychological approach to assessing animal personality can be considered as more exploratory in nature, with several studies lacking a priori hypotheses (Toms,

Echevarria, & Jouandot, 2010). Many of the initial studies looking at personality in animals primarily utilized rating methodologies, so as to apply previously established assessments in humans to a non–human species (e.g., initial use of the Five–Factor Model assessment on chimpanzees; King & Figueredo, 1997).

The Five–Factor Model is the most widely utilized assessment structure for investigating human personality (Block, 1995, 2001; Borkenau & Ostendorf, 1990). It is comprised of five general categories: (1) extraversion, (2) openness to experience, (3) neuroticism, (4) conscientiousness, and (5) agreeableness (Digman, 1990; Norman,

1963). Each factor (e.g., agreeableness) subsumes a large number of more specific traits

(e.g., kind, out-going, affectionate; Digman, 1990; Gosling & John, 1999). Particular factors that comprise a categorical trait differ within the broader category, but the traits that comprise a given Five–Factor Model factor (e.g., agreeableness) reflect core features of that trait group. The Five–Factor Model in humans is identifiable across different countries and is not limited by culture or language (Weiss et al., 2009), which allows for cross-cultural comparisons of personality. Subsequently, several empirical studies have demonstrated that the Five–Factor Model is amendable to personality assessments in some animal species (e.g., Gosling, 1998, 2001; Gosling et al., 2003; Highfill & Kuczaj,

2007; King & Figueredo, 1997) due to the convergent validity observed in human studies. When applying Five–Factor Model traits to non-human animals, individuals are typically rated on a five–point scale continuum within each of the general five factors

(Carter, Marshall, Heinsohn, & Cowlishaw, 2011). Individual differences arise from the consistent, salient, and context -relevant behavioral responses an individual exhibits

(Carlstead et al., 1999; King & Figueredo, 1997). Subsequently, researchers can take diverse descriptive adjectives and condense them in key personality traits homologous to the Five–Factor Model through the use of factor analysis (Gosling, 1998; Svartberg &

Forkman, 2002).

King and Figueredo (1997) first examined chimpanzee personality structure according to the Five–Factor Model, in order to determine whether chimpanzee personality factors were comparable to humans. Forty-three personality traits in 100 chimpanzees across several zoos in the United States were assessed using observer ratings. The study provided the first empirical evidence suggesting that a non-human animal could exhibit personality traits similar to the human Five–Factor Model.

Researchers further investigated whether human factors could be comparable to non– human primates and other animal species. A cross-species review of animal personality by Gosling and John (1999) closely examined 12 studies of personality in non-human animals. The majority of these studies used a sample size of 20 specimens or more, which is atypical due to individual captive facilities having limited access to large groups of animals at one time. Gosling and John (1999) found the traits of extraversion and neuroticism may be generalized across numerous species such as chimpanzees (Dutton et al., 1997), dolphins (Highfill & Kuczaj, 2007, 2010; Kuczaj et al., 2012), fish species such as rainbow trout (Onchorhyncus mykiss; Frost et al., 2007), and octopus (Octopus rubescens; Mather & Anderson, 1993). The agreeableness factor may also be generalizable across different social species discussed in the review, excluding guppies and octopus. This distinction may be attributed to the social nature of behaviors that indicate both agreeableness and lack of agreeableness (e.g., aggressiveness) and may be more obviously present in social species (i.e., chimpanzees, gorillas, dogs, and pigs;

Gosling & John, 1999).

Gosling (2001) discussed the current body of evidence suggesting that several different species may exhibit traits that are derived from the “openness to experience”

factor of the Five–Factor Model. Openness to experience encompasses traits such as curiosity, creativity, and adventurous behavior. Evidence for this trait is limited to the curiosity/exploration and creative traits with more distinctive behavioral indicators such as exploration of novel stimuli or “play” behavior (Gosling & John, 1999). At this time, however, researchers are unable to employ a method to quantitatively measure other indicators of openness to experience in non-human animals such as intellect, novel ideas, and imagination as we currently do not know/understand if animal species have an advanced system of communication such as symbolic expression or language (Gosling &

John, 1999; Gosling, 2001).

Bottlenose dolphins have exhibited personality factors homologous to the human

Five–Factor Model. Highfill and Kuczaj (2007) were the first researchers to investigate such individual differences in personality characteristics for this species. The study employed the rating method comprised of 30 traits derived from the Five–Factor Model on a group of 15 bottlenose dolphins prior to Hurricane Katrina, and 15 months post-

Katrina. During the interval between ratings, the dolphins underwent significant changes to their environment as they were displaced from MarineLife Oceanarium to the

Mississippi Sound, rescued, then relocated to a facility in the Bahamas. MarineLife staff conducted ratings for the first assessment, and new staff members at the Bahamas resort location completed the second set of ratings. Despite the change in staff that completed the ratings, the results revealed that different personalities existed within the group of bottlenose dolphins, indicative of individual differences. Individual personalities were stable from the first rating to the second for 12 of the 15 dolphins, which strengthened the conclusion that dolphins are capable of having stable personalities across time.

While adapting the Five–Factor Model to animals has benefits, there are significant drawbacks and limitations to the use of such a framework with non-human animals. A principal limitation is that only some of these factors apply to non-human animals, while other constructs appear to be species–specific (Gosling & John, 1999).

When trait constructs exhibited in one species are taken and applied to another, such as applying the human Five–Factor Model to non-human species, is known as utilizing a

“top–down approach” to analyzing personality (Freeman et al., 2013). For example, King and Figueredo (1997) utilized the previously established Five-factor Model and applied it to chimpanzees. However, concerns over not utilizing relevant behavioral constructs

(e.g., factors derived from the target species behavioral repertoire), the generality of how

“stability” and “consistency” are measured, and only assessing personality in one context rather than multiple situational or social contexts introduce biases in “top–down” assessments (Freeman et al., 2013; Kuczaj et al., 2012; Massen, Antoindes, Arnold,

Bionda, & Koski, 2013). Thus, subsequent animal personality studies have incorporated species-specific modifications regarding how personality is assessed in order to reduce anthropomorphic interpretations when describing personality traits in different species

(Gosling, 2001; Freeman et al., 2013).

Introducing species–specific constructs and taking into account more contexts of a species’ personality is known as utilizing the “bottom–up approach” to personality assessment (Freeman et al., 2013). Uher and Asendorpf, (2008) utilized a bottom–up approach comparing personalities of chimpanzees, gorillas, and bonobos by using behavioral coding to generate traits derived from each species’ behavioral repertoire.

Koski (2011) also applied species–specific constructs through behavioral coding to

examine personality traits in social contexts and their temporal stability in chimpanzees.

Their results supported the hypothesis that personality traits are exhibited differently in social versus non-social behaviors and contexts. Incorporating different aspects of personality, such as behavior stability, consistency, and different contexts, allows for a more complete picture of personality structure.

Kuczaj et al., (2012) investigated the importance of context and temporal stability in dolphin behavior and personality characteristics by assessing specific traits across three contexts (interactions with the physical world, interactions with other dolphins, and interactions with humans). Twenty dolphins housed at Dolphins Plus in Key Largo,

Florida were rated by animal care staff on the traits “observant,” “timidity,” “curiosity,” and “playful” across the three aforementioned contexts. In a second assessment targeting social behaviors across these social contexts, the characteristics “aggressiveness,”

“gentleness,” and “cooperation” were analyzed over the social contexts (interactions with humans, and interactions with dolphins). Interaction with the physical world is non- social, so it was eliminated from this second assessment. The results indicated that trait consistency across contexts sometimes differed for each dolphin individually. Four of the subjects were stable in all traits across all situations, while the remaining sixteen dolphins’ ratings were more variable across situations. Thus, the study further emphasized the importance of accounting for context and utilizing constructs specific to the target species when assessing individual differences in dolphins and other non-human animals.

Bottlenose dolphins exhibit a fission-fusion social structure and engage in numerous associations and interactions with other group members including mating

alliances, pair bonds, and allo–parental relationships (Connors, Mann, & Watson-Capps,

2006). Therefore the type of associations and relationships an individual engages in could be indicative of their individual personality. Krause et al. (2010) argue that simply assessing behaviors on a dyadic scale only provides a snapshot of an individual’s personality; it is more useful to expand personality assessments to place them in the context of the social network, examining individual-individual interactions and relating them to the population’s social structure. Kuczaj and colleagues (2012), applied this concept to the dolphins with their rating method, and specifically included different social contexts in their analysis. Kuczaj et al. (2012) also identified the importance of validating results from ratings with an assessment of each individual’s behavioral tendencies. Following a social network approach to assessing personality would allow researchers to investigate roles that individual differences may play in different social situations, such as maintaining hierarchical order and resolving social conflict (Krause et al., 2010). Highfill and Kuczaj (2010) discussed examples of different types of social dolphin behavior for both wild and captive populations, where individual differences in personality may serve a role in distinguishing how an individual will behave in relation to the group. Such categories include, but are not limited to, foraging/group hunting (Gazda,

Connor, Edgar, & Cox, 2005), maternal care (Hill, Greer, Solangi, & Kuczaj, 2007), group movements (Lewis, Wartzok, & Heithaus, 2011), cooperation (Kuczaj, Winship, &

Eskelinen, 2014), and formation of a social hierarchy (Krause et al., 2010; Samuels &

Gifford, 1997). Highfill and Kuczaj (2010) further discuss how future analysis of personality across different contexts of dolphin behavior can provide more information regarding the current understanding of dolphin personality. The authors also stress the

importance of distinguishing individual differences that are important to the current understanding of personality, rather than variation that is simply a part of that individual’s behavioral flexibility.

In both wild and captive groups, male and female bottlenose dolphins maintain a dominance hierarchy that is hypothesized to regulate social conflict (Veit & Bojanowski,

1996). Social conflict occurs when individual animals with incompatible goals or attitudes interact. Typically this results in aggressive or agonistic behavior by those individuals towards others (Aureli, Cords, & Van Schaik, 2002). Much of the conflict within the dolphin hierarchy is linked to subdominant individuals, who are typically ranked within the middle (non–stable) of the hierarchy, and actively attempt to advance their social rank (Veit & Bojanowski, 1996). Middle ranked subdominant individuals frequently challenge more dominant individuals to advance their position, as well as defend their current rank from less dominant contenders (Benus, Bohus, Koolhaas, &

Oortmerssen, 1991). As such, instability of social rank results in higher levels of aggressive behaviors persisting amongst those individuals (Scott, Mann, Watson-Capps,

Sargeant, & Connor, 2005). How an individual dolphin reacts when challenged by a dominant or submissive individual may provide insight to that individual’s personality in social situations. For example, aggressiveness and response to defeat when faced with social conflict are indicative of an individual’s dominance rank, as shown through several studies that further examined exploratory measures and behavioral profiles (e.g., great tits

(Parus major; Dingemanse & De Goede, 2004; Verbeek, Boon, & Drent, 1996; Verbeek,

De Goede, Drent, & Wiepkema, 1999) and bottlenose dolphins (Samuels & Gifford,

1997)).

It has been hypothesized that information on the personality construct spectrum of bold–shy would serve as a good predictor for how an individual would behave in this context, but the variation present with operational definitions and measures of boldness make it difficult to determine the validity of bold–shy assessments (Toms & Echevarria,

2014). The bold–shy dimension is considered highly adaptive to several fitness measures including foraging success, exposure to predators, and reproductive success (Brown &

Braithwaite 2004; Colléter & Brown, 2011; Toms et al., 2010; Wilson, Coleman, Clark,

& Biederman, 1993). Chase et al. (2002) suggested that an individual’s position in the dominance hierarchy is the product of both individual differences in physical and behavioral characteristics, and intrinsic social interactions. Most of the previous research focused on the physical attributions associated with dominance, but few studies have investigated the link between personality traits and fitness measures. Colléter and Brown

(2011) found that male rainbowfish (Melanotaenia duboulayi) social position was correlated with personality traits aggression, activity, and boldness. Dominant fish were higher on all three constructs, and were more likely to be reproductively successful. This relationship has yet to be assessed in larger mammal species.

While the relationship between social rank and personality has rarely been assessed in non-human animals, studies examining this relationship in humans have established two categories of traits related to personality in the social-rank workplace environment. The concept driving the development of these groupings is that men and women tend to adopt specific roles in their social groups to enhance their well–being

(Mosher & Danoff-burg, 2005). The first category, “Agentic” traits, are considered to be more masculinized attributes (i.e., active, decisive, dominant; Deaux & LaFrance, 1998;

Ruble & Martin, 1998), and the second category known as “Communal” (i.e., traits such as caring, submissive; Deaux & LaFrance, 1998; Ruble & Martin, 1998) are both present within the workplace hierarchy (Abele 2000, 2003; Carlson, 1971). Much of the previous literature suggests that as a highly agentic individual achieves a high position within the hierarchy, they tend to accumulate more agentic traits the longer they maintain their social position (Eagly, 1987; Wood & Eagly, 2002). Communal traits are typically expressed at higher levels in women and are not tied to occupational roles (Abele, 2000,

2003; Moskowitz, Suh, & Desaulniers, 1994; Philips & Imhoff, 1997; Twenge, 1997).

This may be attributed to a gradual change in the value society places upon the expression of communal traits (Abele, 2003; Twenge, 2001). Yet, when specifically considering the importance of agency and communion in relation to career success, from an evolutionary perspective agency is considered more important than communion

(Abele, 2000, Buss & Kenrick, 1998). No personality studies in non-human animals

(such as cetaceans) have yet attempted to assess 1) personality and its relationship to social rank, and 2) if an accumulation of traits that are more agentic or communal is related to an animal’s position in its social hierarchy.

Current Study

The aim of the present study was to investigate the relationship between dolphin personality and social rank. The bottlenose dolphins used in this study reside at the

Roatan Institute for Marine Sciences in Roatan, Honduras. Animals can be individually identified using physical attributes visible on their dorsal fins, flukes, and body. These include nicks, notches, scars, and differences in pigmentation (Wursig & Wursig, 1977).

Temporary visual characteristics, such as rake marks and scratches, are tracked and

monitored during the seasons to assist in identification. Personality assessments were conducted utilizing ethological coding of approximately 25 hours of underwater video recordings collected during 2011 – 2012. Social rank of each individual dolphin during the data collection period was assessed through questionnaires and interviews with the senior RIMS staff members. They identified individuals that rank as highly dominant, or

“alpha” males and females, subdominant individuals at the bottom of the hierarchy, and middle ranked individuals. For an individual dolphin, each of the personality traits clustered from a correlation matrix analysis was then correlated to relative social rank position. Traits considered agentic or communal that emerged from the analysis were categorized as either of these two factors based upon previously established definitions, and analyzed for age-class and sex differences as well as correlated to social rank. The following hypotheses were addressed: 1) Personality expression will vary across contexts, 2) There will be a correlations between personality traits and social rank, with some composite traits emerging that are homologous to those found in the agentic and communal categories and some that do not fit into those two factors, 3) There will be trait differences between the sexes, 4) There will be personality traits correlated to social rank for separate male and female social rank systems, 5) Males and females with high levels of agentic traits will be ranked higher in the social hierarchy, 6) Female dolphins will exhibit higher levels of communal traits compared to the males. It is important to note that these a priori hypotheses were exploratory in nature, with no predetermined traits being assessed. Labels for composite trait groups found through this study are somewhat subjective. The assigned labels were given with careful consideration of the behaviors

that make up the trait, and interpreted with caution (e.g., as discussed by Toms &

Echevarria, 2014).

CHAPTER II – METHODS

Subjects and Facility

The dolphin social group used for this study is housed at the Roatan Institute for

Marine Sciences located on the north-west side of Roatan island, which is the center of three bay islands on the north of the Honduran coast (Figure 1). The dolphins reside in an enclosed sea pen on the northern side of the island on Bailey’s Key. The enclosure is approximately 8000m2 in area and ranges from the shoreline to approximately 7m in depth. The sea floor consists of coral, sand, and sea-grass beds. During the study period, the population consisted of 25 dolphins, including males and females of varying age classes (i.e., calf –dependent and nursing, sub-adults –independent but not sexually mature, and adults –independent and sexually mature; Eskelinen, Winship, & Borger

Turner, 2015). Two dolphins (Polly and Tilly) were born during data collection for this study (see Table 1).

Figure 1. Aerial photograph of Roatan Institute for Marine Science dolphin enclosure.

Table 1

Demographic Information for RIMS dolphins

Name Sex Birth Date Age Class Polly F 07/25/11 Calf Tilly F 08/14/11 Calf Cortez M 05/02/10 Calf Mickey M 07/11/09 Calf Pigeon F 08/13/09 Calf Vin M 08/04/09 Calf Dixon M 09/04/07 Sub-Adult Anthony M 10/01/05 Sub-Adult Bailey F 10/13/05 Sub-Adult Margarita F 08/14/07 Sub-Adult Mr. French M 08/13/04 Sub-Adult Ken M 09/30/04 Sub-Adult Fiona F 10/25/03 Sub-Adult Ritchie M 10/30/03 Sub-Adult Maury F 01/14/02 Adult Ronnie M 11/10/02 Adult Bill M 12/16/01 Adult Mika F 08/20/01 Adult Alita F 07/06/03 c.d Adult Carmella F 10/30/03 c.d Adult Han Solo M 05/02/09 c.d Adult Gracie F 09/29/98 c.d Adult Hector M 07/06/03 c.d Adult Cedena F 10/03/90 c.d Adult Mrs. Beasley F 12/04/98 c.d Adult Paya M 10/30/89 c.d Adult c.d = capture date. Data Collection

Dr. Stan Kuczaj and other members of the Marine Mammal Behavior and

Cognition Laboratory (MMBCL) at the University of Southern Mississippi collected underwater video data using a camera recording synchronous video and audio data.

Underwater video recordings were collected opportunistically during excursions to

Roatan, Honduras between 2011 and 2012, totaling 24 hours, 44 minutes and 39 seconds

of video data. The data was collected using focal–animal, focal–sub group, and all– occurrence sampling (Altmann, 1974). Focal follows began when an animal came into view and terminated when the animal disappeared from view (Dudzinski, Gregg, Ribic,

& Kuczaj, 2009). Video segments ranged from several seconds to approximately 10 minutes. Data was typically collected in the early morning hours when all subjects were housed together, from approximately 06:00am until 08:00am. Only data in which all the dolphins in the population were housed together was utilized in this study.

Individual animals were identified using sketches, photographs, and video identification interviews of dolphins by their trainers. This information allowed for temporary identifiers such as rake marks and pregnancy states to be used during behavior coding, making identification easier and more accurate.

The social hierarchy during the data collection period was assessed through a questionnaire developed by Erin Frick and Stan Kuczaj, in conjunction with interviews conducted by Stan Kuczaj with several senior members of the training staff at the Roatan

Institute for Marine Sciences (RIMS). These interviews examined separately the male and female hierarchies amongst all individuals at the end of the study period. The animals within each hierarchy were grouped in four sub-groups: highly dominant, moderately dominant, somewhat dominant, and least dominant. Individuals within each group were listed in the approximate rank order from dominant to least dominant. This ranking system was supplied with the caveat that there is some fluctuation in individual rank present depending on the time of year (i.e., seasonality; if any of the females are in estrus and receptive to mating). The majority of the data used in this analysis were collected in

the spring and summer months, so the dominance structure for the purposes of this study could be considered fairly stable across these time periods.

Data Analysis

Each dolphin’s total time spent onscreen (i.e., availability for behavioral coding) was calculated for all 2011 – 2012 videos. Due to the unequal times that each dolphin was recorded on video, any dolphin that was onscreen less than 40% of the total time relative to the dolphin with the most onscreen time was excluded from analysis. These exclusions were conducted separately for each sex. This allowed for sufficient data to assess personality in each dolphin while conserving adequate subjects for the remainder of the study. Thus, three males (Paya and Bill (adults); Cortez (calf)) and three females

(Carmella (adult); Polly and Tilly (calves)) were excluded from future analyses. All subsequent analyses were conducted separately by sex (e.g., male dolphin personality traits were collated separately from the female dolphins), due to the male and female hierarchies being discrete behavioral systems (Aureli et al., 2002; Samuels & Gifford,

1997).

Videos were analyzed by logging all observed behaviors from an ethogram

(adapted from Dudzinski, 1996) and Samuels & Gifford, 1997) (Appendix A) into Excel© sheets that detail the identity of each dolphin and their respective behaviors. The ethogram included 45 behaviors, to account for a variety of behavioral events. All behaviors were coded within each general contextual category of Dolphin Interacting with Dolphin (DID), Dolphin Interacting with Object/Environment (DIO), Dolphin

Interacting with Human (DIH), or Dolphin Interacting Alone (DIA), derived from Kuczaj et al. (2012). The initiator and the recipient of each interaction were noted when

possible, and the duration of each behavior was recorded. Inter-coder reliability was assessed between two coders using approximately 12.5% of the data for dolphin ID, behavior, context, and behavior duration using randomly selected videos from each year.

Using Pearson’s Correlation Coefficient, 86% reliability was achieved.

Behaviors that went unobserved in any context were removed from further analysis. Of the total 45 behaviors initially included, 32 were observed and retained for analysis for the DID context in males, and 28 for the females. In the DIO context, 14 behaviors were recorded for the males and 13 for the females. The DIH context retained

13 behaviors for both males and females, and the DIA context retained 6 behaviors for the males and 5 for the females (see Table 2 for full description). Several behaviors were observed in all 4 contexts, while others only were recorded in one contextual type, and differed slightly between sexes. Recorded behaviors and time spent engaging in each behavior within each context were summed for each individual dolphin providing a separate behavior rate (i.e., total number of events over the total amount of time seen on video) for the two-year study. Individual behavior rates within each context (4) were then summed for a total overall score for each behavior in each of the context categories.

Table 2

Behaviors in each Context Retained for Analysis for Males and Females

Context Sex Male Female Dolphin Interacting with Approach, Avoid/Flee, Bubble Burst, Approach, Avoid/Flee, Bubble Dolphin (DID) Bubble, Bubble Trail, Bite, Chase, Burst, Bubble, Bubble Trail, Erection, Follow, Goosing, Group Chase, Follow, Goosing, Group Social Ball, Head to Head Circling, Social Ball, Head to Head Hit, Head Scanning, Interrupt, Jaw Circling, Hit, Head Scanning, Clap, Mount, Mouthing, Nudge, Interrupt, Jaw Clap, Mouthing, Open Mouth, Orient to Dolphin, Push Open Mouth, Orient to Dolphin, Down, Push Up, Petting, Pec Rub, Push Up, Petting, Pec Rub, Pair Pair Swim, Contact Swim, Ram, Rub, Swim, Contact Swim, Ram, Rub, Sexual Rub, Tactile Tactile

Dolphin Interacting with Approach, Avoid/Flee, Bubble Burst, Approach, Avoid/Flee, Bubble, Human (DIH) Bubble Trail, Exchange, Follow, Hit, Bubble Trail, Exchange, Follow, Head Scanning, Mouthing, Open Head Scanning, Mouthing, Mouth, Orient to Person, Rub, Tactile Nudge, Open Mouth, Orient to Person, Rub, Tactile Dolphin Interacting Approach, Bubble Burst, Bubble, Approach, Bubble Burst, Bubble, Object/Environment Bubble Trail, Bubble Interaction, Bubble Trail, Bottom Grubbing, Bottom Grubbing, Head Scanning, Head Scanning, Jaw Clap, (DIO) Mouthing, Open Mouth, Orient to Mouthing, Open Mouth, Orient to Camera, Orient to Object, Pick Up Camera, Orient to Object, Pick Object, Sand Rubbing Up Object, Sand Rubbing Dolphin Interacting Bubble Burst, Bubble, Bubble Trail, Bubble Burst, Bubble, Bubble Alone (DIA) Erection, Leaping, Open Mouth Trail, Head Scanning, Open Display Mouth See Appendix A for operational definitions Due to the small sample size and unequal data collected per subject, the resulting datasets violated assumptions of homogeneity of variance. Therefore, a factor analysis was not utilized. Spearman’s correlation coefficient was used to create correlation matrices to determine behaviors that could be clustered together for composite trait groups within each context category. The non-parametric test that examines the relationship between two variables is widely accepted as a replacement for traditional factor analysis (Dziuban & Shirkey, 1974). The use of correlation matrix tables to group behaviors significantly correlated together to form trait groups was successfully applied

with elephants by Horback and colleagues (2013). The methodology applied in the current study follows a similar paradigm, but incorporating a greater range of behaviors, and the addition of coding general contextual information for all behaviors. To assess how much each dolphin’s behavioral activity was spent engaging in a particular behavioral event (i.e., open mouth) within each context (e.g., Dolphin Interacting with

Dolphin, Dolphin Interacting with Object/Environment, Dolphin Interacting with

Humans, Dolphin Interacting Alone); individual behavior percentages were calculated to give each individual an overall score for each behavioral event within a context (i.e., bubble trails that occurred in the Dolphin Interacting with Dolphin context). A

Spearman’s correlation coefficient matrix was calculated for all scores observed per behavior within a context group for the male and the female hierarchies separately.

Within each matrix, behaviors correlated with an alpha > 0.05, and had closely related operational definitions, were then clustered together into composite trait groups. The composite trait groups that were created from the correlational matrices for the males and females separately did not observe behaviors cluster in a random pattern, which would have been expected of multiple Type I errors. This suggests that the composite traits were defined by the accumulation of correlations between behavior and related situations

(Horback et al., 2013; Locurto, 2007). Spearman’s rank order correlation was also utilized to determine which of the emergent personality traits were significantly correlated to the social rank position of each individual dolphin, for both the male and female hierarchies separately.

In order to create a personality profile for each dolphin, individuals were labeled as “high”, “medium high”, “medium-low” or “low” for each derived trait based upon

calculated quartile ranks, similarly to how correlation matrix derived traits were placed into personality profiles for elephants (Horback et al., 2013). This process assigns values for the three points that divide the data into a set of four equal groups (i.e., each group comprises one quarter of the data; Altman & Bland, 1994). An individual was labeled as

“high” for a particular trait if their combined trait score fell between the third and fourth quartile, “medium-high” if it fell between the second and third quartile, “low- medium” if the combined trait score fell between the first and the second quartile, and “low” if it fell below the first quartile value.

To assess overall levels of agentic and communal factors in this population, the derived trait groups were sorted into agentic and communal groups based upon previously researched and established definitions of those aspects. Agentic traits are defined as those traits characterized by seeking power and mastery that enhances the individual, observed by frequent aggressive, dominant acts and infrequent submissive acts (Abele, 2003; Eagly, 1987; Locke, 2003). They include characteristics of aggressive, assertive, and decisive traits (Deaux & LaFrance, 1998; Locke, 2003; Ruble & Martin,

1998). Communal traits represent seeking intimacy and bonds with other individuals in a social group, observed through agreeable behaviors and infrequent argumentative behaviors (Locke, 2003). Overall rates of agency and communion per individual were calculated by collapsing all the scores for each trait derived from the correlation matric analysis that could considered to be agentic or communal, based upon the aforementioned operational definitions. In the end, each individual will have one overall score for the agentic factor and another for the communal factor. Spearman rank order correlation determined if any significant correlations between the dolphins rank order and

agentic/communal factors were present. An ANOVA was conducted to determine if there was a significant difference between agentic and communal trait expression and age– class (e.g., adults, sub-adults, calves). Sex differences in male and female levels of agentic and communal factors were compared using Mann-Whitney U test.

CHAPTER III - RESULTS

Social Rank

Based upon the responses to the social rank questionnaire and interviews conducted by Dr. Stan Kuczaj, individuals placed in each group were ranked in order from most dominant to least (Figure 2).

Figure 2. Social rank for the (A) males and (B) female dolphins at RIMS.

Dolphins are listed from most dominant to least from top to bottom. Age–class for each animal is indicated: A = Adult, SA = Sub

Adult, C = calf. Personality

Spearman’s correlation coefficients were calculated for each of the behaviors observed within each context group for the males and the females separately, resulting in

8 matrices. The male matrix for the Dolphin Interacting Alone (DIA) context was eliminated, as none of the behaviors were significantly correlated, retaining 7 matrices for clustering composite trait groups (see all matrices in Appendix B). Within a given matrix, behaviors correlated with an alpha < 0.05, and had closely related operational definitions, 25

were then clustered together into composite trait groups. In the end, 13 composite trait groups emerged for the males, and 12 were revealed for the females. For the males, curious and contact-seeking traits were observed in multiple contexts. The context of

Dolphin Interacting with Dolphin (DID) for the males revealed the traits curious, sexual, propinquity, aggressive, combative, bothersome, sociable, and camaraderie. Males also exhibited traits of curious, evasive, and exploratory for the Dolphin Interacting with

Humans (DIH) context. Lastly, traits of playful, investigative, contact seeking were observed in the Dolphin Interacting with Object/Environment (DIO) context (Table 3).

Traits that emerged for the females for DID were propinquity, excitable, aggressive, surgency, affiliative, confrontational, and observant. Females exhibited the traits of playful and curious for DIO, interactive and evasive for DIH, and lastly, showing– interest, for the context of DIA (Table 4). Labels were chosen based upon the types of behaviors and contexts that were significantly correlated to each other.

Table 3

Composite Personality Traits for Male Dolphins

Traits (Context) Significantly Correlated Behaviors Curious (DID); (DIH) Approach, Bubble Trail; Approach, Bubble Burst Sexual (DID) Avoid/Flee, Bubble Burst, Erection, Group Social Ball, Mount, Rub, Push Down Propinquity (DID) Pair Swim with Contact, (-) Hit Aggressive (DID) Jaw Clap, Bite, Head Scan Combative (DID) Head to Head Circling, Mouthing, Open Mouth Display, Ram

Bothersome (DID) Interrupt, Nudge, Push up Sociable (DID) Petting, Tactile, Chase Camaraderie (DID) Pair Swim, Pectoral Rub Playful (DIO) Approach, Bubble Burst, Mouthing, Open Mouth Display Investigative (DIO) Bubble Interaction, Bottom Grubbing Contact Seeking Sand Rubbing, Pick Up Object; Rub, Tactile (DIO); (DIH) Evasive (DIH) Avoid/Flee, Hit Exploratory (DIH) Mouthing, Open Mouth Display

Table 4

Composite Personality Traits for Female Dolphins

Traits (Context) Significantly Correlated Behaviors Propinquity (DID) Pair Swim with Contact, (-) Avoid/Flee Excitable (DID) Bubble Burst, Group Social Ball Aggressive (DID) Bubble, Jaw Clap, Ram, Goosing Surgency (DID) Chase, Hit, Open Mouth Display, Interrupt Affiliative (DID) Bubble Trail, Petting, Rub, Pectoral Rub, Pair Swim Confrontational (DID) Head to Head Circling, Head Scanning Observant (DID) Follow, (-) Rub Playful (DIO) Approach, Pick up Object, Bubble Trail, Mouthing, Open Mouth Display Curious (DIO) Orient to Object, Bubble Burst Interactive (DIH) Approach, Bubble Trail, Exchange, Head Scanning, Mouthing, Nudge, Open Mouth Display, Rub, Tactile Evasive (DIH) Avoid/Flee, (-) Orient to Person

Showing-Interest Bubble Trail, Open Mouth Display (DIA)

All individuals were given a score for each composite trait group. These scores were based upon the summation of all total fractions of time the individuals spent engaging in all behavior types for a composite group, out of its total time observed. Not

all dolphins expressed each trait. Calculated quartile ranks for each personality trait facilitated the creation of personality profiles for all males (Table 5) and all females

(Table 6).

Table 5

Personality Profile for the Male Dolphins

Hector Han Ritchie Ronnie French Ken Anthony Dixon Vin Mickey Solo Curious M/H M/L L L H M/L H M/H M/H M/L (DID) Curious M/H M/L - H M/H M/H - L M/L M/H (DIH) Sexual (DID) L L M/L M/L M/H M/H M/H H H H Propinquity H L L M/L M/L L M/H L M/H M/L (DID) Aggressive M/L H H M/H H - M/L M/H M/L - (DID) Combative L M/H M/L L H M/L H M/L H L (DID) Bothersome L M/L M/L L M/H H M/H H H L (DID) Sociable H H M/H M/H L L M/L H M/L M/L (DID) Camaraderie H H M/H M/L H L M/L L M/L M/H (DID) Playful (DIO) M/L M/L - H M/H H M/L M/H M/H H

Investigative M/H M/H - H H - - - - - (DIO) Contact ------H H Seeking (DIO) Contact - - - H H M/H - - M/L M/H Seeking (DIH) Evasive - H ------(DIH) Exploratory M/H - M/L H M/H M/L M/L H L M/H (DIH)

Note: H = High, M/H = Medium-High, M/L = Medium-Low, L = Low. Dolphins are listed in descending order of social rank.

Table 6

Personality Profile for the Female Dolphins

Mrs. Cedena Alita Gracie Mika Fiona Maury Bailey Margarita Pigeon Beasley Propinquity M/L M/H M/ L M/H L H M/L L M/L (DID) H Excitable L M/H H L H M/H M/L H M/H M/L (DID) Aggressive ------H H - (DID) Surgency H M/H L H L M/L L M/H M/H M/L (DID) Affiliative L L M/ M/L M/H M/L M/L H H H (DID) H Confrontati ------H H - onal (DID) Observant H H - - - M/L - M/L - M/H (DID) Playful - - M/L L M/L H M/H M/H H M/L (DIO) Curious ------H H - (DIO) Interactive - - - - - M/H M/H M/H H - (DIH) Evasive H M/H H M/H M/L M/L L L M/L L (DIH) Showing- - - M/L M/H - H - M/L M/H M/H Interest (DIA) Note: H = High, M/H = Medium-High, M/L = Medium-Low, L = Low. Dolphins are listed in descending order of social rank.

Personality and Social Rank

Males

Personality scores for each individual male were compared to their relative social rank position in the male hierarchy utilizing Spearman’s rank correlation coefficient.

Trait scores for sexual (DID) (r2 (10) = 0.927, p < 0.05) and contact-seeking (DIO) (r2

(10) = 0.701, p < 0.05 were significantly positively correlated to rank number in the hierarchy (Figure 3). Male dolphins with higher sexual (DID) and contact-seeking (DIO) trait scores were individuals that were lower in the hierarchy. Conversely, males at the top of the hierarchy (i.e., 1st position) were more likely to have lower scores for those trait groups. Trait scores for camaraderie (DID) (r2 (10) = -0.673, p < 0.05) were significantly higher in individuals with higher social status. Trait scores for camaraderie

(DID) were lower for males lower in social rank. All other trait groups were not significantly related to social rank for the male dolphins in this population.

0.3 Sexual (DID) Camaraderie (DID) Contact Seeking (DIO) 0.25

0.2

0.15

FactorScore 0.1

0.05

0 Hector Han Solo Ritchie Ronnie French Ken Anthony Dixon Vin Mickey Dolphin ID Figure 3. Personality traits significantly correlated to social rank in male dolphins.

Males are listed from most dominant to least (left to right).

Females

Trait scores for playful (DIO) and evasive (DIH) were significantly correlated to social rank (Figure 4). Trait scores for playful (DIO) had a strong positive correlation to

th having a higher number in the social rank (i.e., 9 position), (r2 (10) = 0.815, p < 0.05), indicating that trait scores were higher for individuals with lower social status.

Conversely females at the top of the hierarchy (i.e., 2nd position) were likely to have lower scores for this trait group. The trait evasive (DIH) had a strong negative correlation

(r2 (10) = -0.790, p < 0.05), where trait scores were significantly higher in individuals ranked at the top of the hierarchy. Lower trait scores for evasive (DIH) were exhibited by those at the bottom of the hierarchy. All other trait groups were not significantly related to social rank for the female dolphins.

0.08 Playful (DIO) Evasive (DIH) 0.07 0.06 0.05 0.04 0.03

FactorScore 0.02 0.01 0 -0.01

Dolphin ID Figure 4. Personality trait scores significantly related to social rank for females.

Females are listed from most dominant to least (left to right).

Agentic and Communal Factors

In keeping with previously operationally defined components of agency and communal factors, for this study the Dolphin Interaction with Dolphin context male traits of aggressive, combative, and female traits of aggressive, surgency, and confrontational were all categorized as agentic traits. The Dolphin Interacting with Dolphin male trait camaraderie, and the female traits affiliative, observant, and the trait propinquity

(exhibited by both sexes) were considered components of communal factor. All remaining traits were not considered to be clear components of agency or communion.

All scores for traits considered agentic were collated into one agentic factor. All scores for traits considered communal were collated into one communal factor. This was done for both males (Figure 5) and females (Figure 6).

There was no significant effect of age-class on agentic (F(2, 17) = 0.616, n.s)

(Figure 7) or communal (F(2, 17) = 1.808, n.s) trait expression (Figure 8). However, the data shows a marked decrease in scores for agency from adults to calves, but the small sample size and exclusion of two calves (Polly & Tilly) may contribute to this non- significant finding. Communal trait expression was significantly higher in females compared to males (U = 15, p < 0.05). However, agentic personality trait scores did not differ significantly between males and females (U = 27, n.s). In addition, both agentic and communal traits were not significantly correlated with social rank in the male or female hierarchies, and there were no significant differences in agentic and communal trait expression found within or between any of the social rank groups (for example, comparing agentic/communal scores between males at the top of the hierarchy to those at the bottom, middle, etc.,).

Agentic 0.5 Communal

0.4

0.3

0.2 FactorScores 0.1

0 Hector Han Ritchie Ronnie French Ken Dixon Anthony Vin Mickey Solo Dolphin ID

Figure 5. Agentic and communal scores in the male hierarchy.

Neither agentic nor communal factors were significantly correlated to social rank.

Agentic 0.5 Communal

0.4

0.3

0.2 FactorScore

0.1

Dolphin ID

Figure 6. Agentic and communal scores in the female hierarchy.

Neither agentic nor communal factors were significantly related to social rank. Communal factors were significantly higher in females.

Figure 7. Mean agentic scores.

No significant differences were present in scores between adults, sub-adults, and calves.

Figure 8. Mean communal scores.

No significant differences were observed between adults, sub-adults, and calves.

CHAPTER IV – DISCUSSION

The goals of the present study were to (1) identify personality traits in bottlenose dolphins through the use of behavioral coding and (2) relate emergent personality traits to the social rank for the study population in order to establish if any correlative relationship was present. Several of the outlined hypotheses were supported by the results of this study. The use of the coding methodology was successful in extracting several composite trait groups for males and females of the study population. Several trait groups were similarly expressed in both males and females, while other emergent trait groups appeared to be sex-specific, supporting the hypothesis that there would be trait differences amongst the sexes. In addition, there were personality traits that were significantly correlated with an individual’s social rank, indicating that personality may influence an individual’s ability to both obtain and maintain their position in the social hierarchy.

Relationship between Personality and Social Rank

For both males and females, this study provided support for the hypothesis that certain personality traits are correlated with certain characteristics of social rank systems.

For the males, the personality traits sexual (DID), camaraderie (DID), and contact– seeking (DIO) were significantly correlated with an individual’s social rank (p < 0.05).

However, the contact-seeking personality component was only exhibited in the two lowest ranking individuals, Vin and Mickey, who also were the two youngest male calves in the group. These significant findings could possibly be attributed to the stark contrast between the lack of contact–seeking (DIO) present in all other dolphins and the high scores present for the two youngest animals. Thus, their overall exhibition of this trait

may be more indicative of age-related influences on personality expression, and not a significant factor related to dominance structure. While age–class comparisons were not conducted for all personality factors at this time, utilizing a fine-scale age–class comparison in future work with this dataset could reveal more conclusive age–related influences on personality expression in dolphins.

For the sexual (DID) personality component, the expression of this trait was almost completely representative of same-sex behaviors between males. Very few instances of heterosexual mating behavior were observed, and when recorded it was typically involved a male ranked toward the top of the hierarchy mating with a female who was also highly ranked. When assessing fitness measures, individuals at the top of their respective social hierarchy may be afforded more access to resources, including access to female mating partners. For example, Colléter and Brown (2011) found that male rainbow fish social position was correlated to personality traits, with more dominant fish more likely to be reproductively successful. In the present study, males that occupied higher social rank positions likely had preferential access to receptive females for mating opportunities, which were largely unobserved on video, and thus had lower expression of the sexual trait (DID). Sexual may have been expressed more frequently by lower- ranking individuals due to their inability to access females for mating opportunities, and thus these behaviors were observed in a same–sex context predominantly. All males regardless of rank expressed some degree of the sexual trait, but individuals in the lower half of the hierarchy were more often the initiators and recipients of same–sex behaviors encompassed in the sexual trait.

Socio–sexual behaviors such as these are also thought to reinforce developing dominance relationships between a particular dyad, and as such, may reduce the likelihood of incipient aggression (Mann, 2006). The majority of social conflict occurs amongst mid-ranking and lower ranking individuals (Benus et al., 1991); thus, the prevalence of socio–sexual behaviors may communicate social rank information without the need for aggressive behavior (Mann, 2006; Wickler, 1967). This suggests that a sexual (DID) trait could potentially have an adaptive value for sub–adults who are mid/low ranked in the hierarchy, and do not want to be recipients of highly aggressive behaviors (e.g., bites, hits) that may cause injury.

Wickler (1967) was one of the first to suggest that socio–sexual behaviors could also serve an adaptive social function. Calves and juveniles engage in homosexual behavior more frequently than older individuals, possibly in a form of socio-sexual play that may potentially acquire a social rank–related function over time. Mann (2006) suggests that these socio-sexual exchanges in male dolphins help negotiate the formation of long-term bonds, such as male alliances via the number of partners and the frequency of role exchanges within a dyad. For example, mounting behavior (i.e., when a dolphin’s genital area is thrust onto another dolphin’s genital area; Dudzinski, 1996) is thought to be an expression of dominance, with the actor assuming the more dominant position and the recipient adopting a submissive role (Mann, 2006). When reciprocated, this establishes trust as both individuals make themselves vulnerable to their partner by exposing the genital area to other males. Such patterns in partnerships have been exhibited in dolphins (Connor, Smolker, & Richard, 1992). Thus, males with higher levels of sexual personality expression may be related to their search for long-term bond

partners, while males at the top of the hierarchy have established long-term bonds with other males and no longer exhibit high levels of sexual personality expression.

Camaraderie (DID) was exhibited significantly more amongst higher-ranking males, and this correlative relationship may allude to the importance of male alliance formation and maintenance in older, sexually reproductive males. Male bottlenose dolphins have been known to form dyad or triad alliances to sequester females for increased mating opportunities and other resources (Connor, Heithaus, & Barre, 2001;

Connor et al., 1992; Connor & Whitehead, 2005). As such, a continued expression of seeking out associations with other individuals may potentially be beneficial to forming/maintaining such alliances. Primary behaviors comprising this composite trait included pair swim and pectoral rubbing, both considered affiliative behaviors in cetaceans (Dudzinski, 1998). Pectoral rubbing involves active movement of the pectoral fin to rub a part of another dolphin’s body (Dudzinski, 1996). Pectoral rubbing tends to exhibit frequent role exchange between participating individuals, suggesting that it is an affiliative social behavior that serves a beneficial function (Sakai, Hishii, Takeda, &

Kohshima, 2006). Adults and sub–adults tend to engage in rubbing behaviors with individuals of the same sex and age–class in order to maintain an already established alliance or bond (Dudzinski, 1998; Dudzinski et al., 2012; Sakai et al., 2006). In addition, individuals with high coefficient of association (COA) observed in male alliances are comparable to those of a mother-calf dyad (Conner et al., 1992; Conner et al., 2006). In the present study, the two highest–ranking males, Hector and Han Solo, are known to have a coefficient of association of 0.81, which is indicative of a high level of association

(Harvey, 2015). These two individuals exhibited the highest trait scores of camaraderie

(DID) compared to all other males, which supports the notion that this trait expression may be related to facilitation and maintenance of their possible alliance. Camaraderie

(DID) was also exhibited in comparably high levels for all males, which could be due to the development of new male–male bonds that may eventually translate into an allied pair.

The traits of playful (DIO) and evasive (DIH) were significantly related to social rank for the females in the study population. While none of the Dolphin Interacting with

Dolphin context group traits had a significant relationship with social rank, it is possible that the playful (DIO) trait is representative of a social component of dolphin behavior known as stimulus enhancement. Stimulus enhancement occurs when the observation of an action leads the observer to increase the proportion of their behavior directed toward the location or object of the demonstrator’s activity (Bender et al., 2009). This focusing of behavior increases the likelihood that the observer will achieve the same response as the demonstrator (Paletis, 2004). While stimulus enhancement is considered an established sub–category of social learning (Kuzcaj, Makecha, Trone, Paulos, & Ramos,

2006), very little research has been conducted to clearly demonstrate its occurrence.

While stimulus enhancement was not assessed directly in this study, it was often observed that one individual’s attention toward an object (i.e., sea grass, floating trash, shell) typically resulted in several other individuals appearing and also attempting to interact with the same object. Similarly, play behaviors in dolphins are thought to indicate the ontogeny of problem solving skills through spontaneous imitation and observational learning of play behaviors by calves and juveniles (Kuczaj & Yeater, 2006;

Kuczaj & Horback, 2013). Dolphins exhibit individual differences in the bold–shy

dimension of personality that are present from an early age (Highfill & Kuczaj, 2007;

Mann, 1997). Individuals that are more bold and curious tend to be more likely to have their behavior mimicked and modeled by other dolphins in a given social group (Kuczaj et al., 2006; Kuczaj et al., 2012). Additionally, younger dolphins are more likely to engage in novel play, and are considered important to the transmission of play within a social group (Kuczaj & Eskelinen, 2014). Calves and juveniles were ranked low in hierarchy, and differences in playful behaviors/playful traits may be related to age-class components as well as dominance status.

The evasive (DIH) trait for females was only observed in individuals that occupied the highest social rank positions. Historically, bottlenose dolphins have long been exposed to human interaction, whether via interactions with tourism vessels, with fishing boats, dolphin swim programs offered at captive facilities, or by lone/group interactions in the wild (Acevedo, 1991a, 1991b; Bejeder, Samuels, Whitehead, Finn, &

Allen, 2009; Constantine, 2001). Responses of dolphins to human presence include habituation, tolerance, and neophobia/neophilia. Habituation can refer an individual’s decrease in a behavior response to novel stimuli (e.g., exploratory behavior; Leussis &

Bolivar, 2006) when it is repeated frequently with no reward or punishment (Bejder et al.,

2009; Costantine, 2001). Tolerance refers to no behavioral response apparent (i.e., neutral) when encountering a novel stimulus (Acevedo, 1991a; Bejder et al., 2009).

Neophobia is defined as an avoidance or apprehension to a perceived threat or danger in response to a novel stimuli, whereas neophilia is the opposite, described as approaching and exploration of a novel stimuli (Fu et al., 2013) Such neophobic and neophilic

behaviors in response to a novel stimuli such as human presence have been reported in wild populations (Constantine, 2001).

The trait evasive (DIH) was only observed in the top -ranked individuals, which also are the oldest individuals in the population, several of which were originally brought in from the wild. Age-related increases in neophobic responses have been observed previously (e.g., older individuals exhibit weaker response towards novel stimuli;

Huffman, 1996; Kummer & Goodall, 1985; Mayeaux & Mason, 1998). Age may thus influence the expression of this evasiveness trait in older dolphins, as observed by other personality components related to interacting with humans (such as interactive (DIH)) that were expressed more in younger individuals. Younger dolphins tend to engage in more “play” behaviors than older individuals (Kuczaj et al., 2002, 2006), which may result in their increased likelihood to seek out and interact with novel stimuli in their environment, such as human swimmers, divers, or researchers swimming with a large camera. Lopes, Borger-Turner, Eskelinen, & Kuczaj (2016) observed neophilic responses to novel stimuli more often in dolphins that had strong social bonds to other adults, suggesting that social affiliation may be a strong factor in the decision to approach novel stimuli and determine its threat potential (Neumann & Orams, 2006). In particular, for mothers and calves, while the older females in this study were more likely to avoid the humans present, they still maintained some proximity to their calves who did approach and interact with humans. Thusly, this may have influenced the calf’s increased expression of the Dolphin Interacting with Human trait interactive and decreased expression of the trait evasive.

Additionally, the study facility conducts numerous dolphin swim programs daily, which include a dolphin interaction and free swim snorkel, dolphin dive, and dolphin action swim. Typically, the individuals involved in this program are the female dolphins and several of the younger males. Experienced staff members accompany all dolphins that participate in program interactions, and each dolphin has both primary and secondary trainers (S. Kuczaj, personal communication, May 2015). Many of the older females used in the interaction programs are accompanied by their trainer, and have been observed to approach and seek out trainers and other familiar personnel. Dolphins can discriminate between familiar and unfamiliar stimuli (Thieltges, Lemasson, Kuczaj, Böye, & Blois-

Heulin, 2011). Thus, the higher expression of the trait evasive could be attributed to the researchers being unfamiliar, and the expression of Dolphin Interacting with Human contextual traits of evasive and interactive could have been different if familiar humans were present. Additionally, only the older males are typically involved in the action swim program, as well as the dolphin dives. The older females are not used frequently in action swim programs (S. Kuczaj, personal communication, May 2015). This decreased exposure to voluntary interaction with humans in the water may also cultivate evasive

(DIH) personality traits when unfamiliar humans were present in the water. Regardless, the significant correlation found in the current study should not be interpreted as the animals being evasive with all humans. As data was collected only with human researchers present in the water, a more fine-scale analysis with a variety of dolphin- human interactions could reveal new information.

An interesting finding that emerged was that none of the traits from the dolphin interacting with dolphin (DID) context were significantly correlated to social rank for the

female hierarchy. This does not necessarily suggest that there is no relationship between these two factors; rather, it is likely that certain aspects of these conspecific-specific traits may not have been captured on video, due to the opportunistic collection of data. One elucidation is that the evasive (DIH) trait, which was also significantly correlated to social rank for females, does suggest that many of the more dominant females would tend to not interact around the recording devices, and would likely swim away from the researcher more frequently than the males. However, there is some literature suggesting that the presence of males may drive females away in order to decrease the likelihood of being consorted, being recipients of aggression, and to protect calves from being recipients of aggressive or rough behaviors (Connor et al., 1992).

Another explanation for the observed patterns of behavior relates to unequal number of focal hours obtained for each individual. This limitation of the dataset could largely contribute to the lack of a relationship between social status and DID context behaviors. The enclosure area of 8000m2 allows for the animals to completely avoid being recorded if they did not wish to be near the researcher. For the most dominant female, Mrs. Beasley, while she was observed frequently on camera, this was more a function of her calf, Vin, who frequently sought out interactions with the researcher and with conspecifics near the researcher. Thus, the interaction of social relationships and associations most likely influences how often certain animals—and in what kind of social context—they are recorded. The inability to consistently focal–follow individuals for a set time period contributes to this limitation of this study. The evasive (DIH) trait, which was also significantly correlated to social rank, does suggest that for many of the females,

they would tend to not interact around the camera, and would swim out of the way more quickly than the males.

Sex-Differences

In the present study, there were differences present for the different types of personality traits expressed based upon the sex of the dolphins. The traits from the

Dolphin Interacting with Dolphin context (curious, sexual, combative, bothersome, sociable, , camaraderie,, investigative), Dolphin Interacting with Object (contact- seeking), and Dolphin Interacting with Humans (curious, contact-seeking, and exploratory) were only observed in males. The traits from contexts Dolphin Interacting with Dolphin (excitable, intervening, affiliative, confrontational, and observant), Dolphin

Interacting with Object (curious), Dolphin Interacting with Human (interactive), and

Dolphin Interacting Alone (showing–interest) were only observed in the females. It could be argued that several of these components could be placed under a larger dimensional structure, such as the combative (DID) trait observed in males and the confrontational

(DID) trait observed in females. Both trait words have connotations that indicate a larger factor structure, such as “Antagonistic”, but as the behaviors associated with each trait differed in that the males were prone to interact and challenge each other more compared to the females who only had the facing-off/challenge component, the trait groups were named differently to account for those subtle behavioral differences (Latzman et al.,

2014; Toms et al., 2010). Researchers have yet to explicitly investigate the hierarchical nature of personality among non-human animals, but future studies that utilize species– specific approaches such as the current study, but can also account for hierarchical

personality structure will be critical for confirming the cross–species nature of trait personality (Latzmann et al., 2014).

For both sexes, DID traits of propinquity, aggressive, DIO trait playful, and DIH trait evasive emerged, suggesting they are personality components that are adapted and cultivated in both sexes. The shared personality traits between males and females could have evolutionarily adaptive significance. For example, both sexes may attribute an adaptive value to a personality component of propinquity (DID) in which individuals high on this trait were more likely to seek out close synchronized affiliative contact with other individuals. Young calves rely on their mother for protection and resources during their first years of life (Hill et al., 2007; Mann, 1997), and thus having mothers and other females (i.e., allo–parenting) who actively seek out maintenance of a close physical connection to a calf (and vice versa) would be beneficial to increasing the likelihood of calf survival (Mann & Smuts, 1998). Males may also seek close affiliative and prolonged contact with females in order to garner mating opportunities as well as prevent the female from mating with another male (Connor et al., 2001).

In studies of human personality, several biological and social psychological theories have offered possible explanation for sex–differences in personality expression.

From an evolutionary standpoint, females have been more invested than males in child- rearing practices (Buss & Kenrick, 1998; Trivers, 1972). Thus, females who were more nurturing may have promoted the survival of their offspring and gained an evolutionary advantage. Dolphin Interacting with Dolphin traits of propinquity, observant, and affiliative, while not significantly correlated to social rank, may be relevant to behavioral events that have been previously established as linked to maternal style and allo–

parenting (Hill et al., 2007). The expression of these traits by the females who had offspring at the time of data collection for the current study varied, suggesting individual differences in maternal styles persist within this population.

Overall, sex differences were present in overall scores for agentic and communal factors. The expression of these two categories of personality traits in humans are typically sex–segregated, in that males are thought to exhibit higher levels of agentic behaviors and females are thought to exhibit higher levels of communal behaviors

(Abele, 2000, 2003; Locke, 2003; Twenge, 2001). Agentic traits are defined as seeking power and mastery that enhances the individual, characterized by frequent dominant acts and infrequent submissive acts (Locke, 2003; Moskowitz et al., 1994). In this study, traits considered agentic included the male Dolphin Interacting with Dolphin (DID) trait groups aggressive, combative, and female DID trait groups aggressive, surgency, and confrontational. No other trait groups conclusively fit within these criteria. In humans, higher levels of agentic traits are present in males compared to females in a hierarchical context (Abele, 2000, 2003; Eagly, 1987; Wood & Eagly, 2002). In this dolphin population, there were no significant differences in agentic trait scores between males and females, nor were agentic trait scores related to social rank. This may suggest that dominance and social rank may be attributed to other factors rather than levels of agency and communion, (e.g., similar to trends in women in the workplace; Abele, 2003).

However, since all dolphins were able to freely swim in a large enclosure and move much faster than a human diver, many of the fast-acting and assertive behaviors that comprise agentic traits may have been minimally recorded, due to limitations of the camera visibility and water visibility. Implementation of a data collection method that allows for

improved long–term visibility of fast/active behaviors would be very valuable when determining more accurately how agency is related to dominance in dolphins.

Dolphin Interacting with Dolphin traits for males of camaraderie, and female trait groups affiliative, observant and the trait propinquity exhibited by both sexes were considered components of communal factor. Communal traits represent seeking associations and bonds with other individuals in a social group, observed through agreeable behaviors and infrequent argumentative behaviors (Locke, 2003; Moskowitz et al., 1994). The communal factor was not related to social rank, but females overall exhibited significantly higher scores for communal factors compared to the males.

Mother–calf associations are one of the strongest bonds in cetaceans (Bender, et al.,

2009) and allo–parenting that persists in bottlenose dolphin populations is typically observed with adult and sub–adult females (Hill et al., 2007; Mann & Smuts, 1998), which may have largely contributed to the higher communal scores for females compared to males. Additionally, the importance of the female–female and mother–calf bonds to the survival of calves and group members (Reidman, 1982) may also influence how traits that are considered communal may be more important to dolphins from an evolutionary standpoint, and are thus selected for and expressed by the majority of the individuals in the population.

Limitations

One of the primary limiting components of this study was the inability to obtain equal amounts of data for each dolphin. While the data was standardized for each dolphin to minimize the effects of time differences across individuals, future studies should control for this variable to the best of their ability. Due to the opportunistic nature of data

collection, the researcher was unable to control which dolphins were recorded and for how long. Bottlenose dolphins are known to swim at speeds up to 8.2 meters per second

(Rohr, Fish, & Gilpatrick, 2002); thus, individual dolphins can swim onscreen and off screen very quickly. Focal–follows were dependent upon the dolphins interacting and traveling within range of the camera, at speeds that the researcher could keep up with.

Additionally, only the data obtained during several week–long excursions were available for analysis. Given the nature of the research, there was no consistent monthly or weekly data collection process. The facility in Roatan is remote, and access to the animals was dependent upon travel availability and the schedule of the RIMS facility.

However, utilizing data from a naturally housed population of this size allows for results to be more generalizable to other dolphin populations, as the dolphins at RIMS are allowed to interact as they naturally would during the off-hours in a natural setting

(Dudzinski et al., 2009). Developing a way to better control data collection to obtain equal amounts of data for each dolphin in a naturalistic and semi–controlled environment such as the one found at RIMS would allow for a more valid analysis of each individuals’ behavioral repertoire for personality.

A constant confound present in the methodology of this research was a human researcher present in the water at all times, as they were carrying the recording devices necessary for data collection. For many of the social behaviors, it is probable that some dolphins may not want to interact or be near the camera, or the presence of the human researcher may have influenced their behaviors in all contexts recorded. Thus, results from this study should be interpreted cautiously, especially when assessing the social

(DID) components, as one dolphin’s score on such traits could be different if the human

researcher was removed. Methods that limit the human presence in data collection may record more diverse and complete social interactions and behaviors than the current methodology used. Additionally, a fine-scale social context analysis could further reveal new information.

While the current study characterized its results as personality, there is still much debate between the criteria for personality (Highfill & Kuczaj, 2007, 2010; Gosling,

2001) versus coping styles (Koolhaas et al., 1999) or behavioral syndromes (Sih, Bell, &

Johnson, 2004). A better consensus is needed regarding operational definitions for all terms referring to components of animal personality in this body of research.

Additionally, psychological approaches to personality assessment in large mammalian species are prone to exhibit subjective biases, especially when labeling emergent trait groups. An important consideration with any design regarding personality or personality traits should be to incorporate methods that will help increase the internal and external validity of the constructs of interest, and reduce anthropomorphic biases (Toms et al.,

2010).

Future Directions

Largely, animal personality research typically focuses on 4–5 factors that emerge for each group being assessed (Gosling, 2001; Kuczaj et al., 2012; Locurto, 2007; Toms

& Echevarria, 2014; Vazire & Gosling, 2004). Future research should attempt to conduct individual personality analyses based upon each individual animal’s repertoire, rather than focusing on group–level traits. Such individualistic assessments may contribute to the field by identifying underlying dimensional structures of personality, or confirming hypotheses about defining personality along a continuum. As observed with the variety of

individual differences present in the traits revealed of this study, this dataset could be further utilized to explore this area of research. A more fine scale analysis of the Dolphin

Interacting with Dolphin (DID) context from the current study, looking at age–class comparisons, may reveal new information on such individual differences, and is the next step for the data in this study.

Additionally, the relationship between related individuals and personality.

Dolphins’ maternal lineage is documented, as well as which individuals are biologically related. Personality similarities or differences between related individuals could provide new insights into the effects of kinship on personality for cetaceans. Further analysis of the current data set incorporating mother-calf and biological comparisons may reveal new information on such relationships.

Conclusions

This study is a preliminary, yet important step to begin to incorporate situational and societal components into the study of non-human animal personality. In particular, species that exhibit a large and complex social structure, such as bottlenose dolphins, may illustrate the psychological aspects of behavior that influence dominance in a given social group. The results from this study suggest that a relationship between personality and an individual’s social status is complex. For example, the most dominant male in a social group may not necessarily be the most aggressive or most bold animal. Individuals ranked at both extremes of the hierarchy (highest and lowest) appear to exhibit a more cleanly correlative relationship between personality and social status, but this was more apparent in the male hierarchy compared to the female hierarchy. However, other factors appeared to influence and vary this relationship for middle-ranked dolphins. For example,

a dominant female that exhibits a cosseting maternal style, will have an influence how her calves behaviorally develop, as well as how others (including more dominant animals) behave toward them. Agentic and communal factors, while present, may not exhibit a relationship to social rank as is observed in human studies. Thus, our results suggest that factors such as age, strength of associations between individuals, maternal style, and interactions between the male and female hierarchies all influence how personality is expressed in different contexts. Future research should begin to incorporate these variables in new and unique ways to broaden our knowledge in this body of research.

APPENDIX A – Ethogram Table A1.

Operational Definitions of Behaviors Coded

Code Behavior Operational Definition APP Approach One dolphin approaches another AVF Avoid/Flee Abrupt, rapid, and immediate departure in response to action of another dolphin, or person BBB Bubble burst Dolphin produces large bubble(s) from blowhole similar to a cloud. BBI Bubble Interaction Dolphin actively manipulates bubbles/stream of bubbles with its rostrum/mouth, pectoral fin(s), or flukes BBL Bubble Single bubble emerged from blowhole BBR Bubble Ring Air ring which slowly surfaces from blowhole BBT Bubble trail Dolphin produces a series of small bubbles from blowhole that form a narrow stream BTG Bottom Grubbing Inverted vertically, dolphin rostrum near seafloor and entire body is rotating BTE Bite/rake Dolphin closes mouth with force around another dolphin, or rubs or slides it’s open jaw along another with its teeth EOR Erection Dolphin has a penile erection, note in comments if the erection is directed toward another dolphin, person, or object. EXC Exchange One dolphin gives something to another dolphin or person (i.e., fish, seaweed, or other object) CHS Chase Rapid and persistent pursuit of another dolphin FIK Bury Flukes in Dolphin actively covers flukes into the sand Sand FLW Follow One animal follows behind another more than one body length GOO Goosing Actor inspects the genital area of the recipient with its rostrum. GRP Group swim Three or more dolphins are swimming in same direction within a (dolphin) body length of each other. ~1.5 meters (Note ID’s in parenthesis) GSB Group social ball Three or more dolphins swim around each other and appear to be “wrestling”, such that it is extremely difficult to identify the individual behaviors in which each animal is engaged HHC Head to Head Two dolphins positioned head to head, circling around Circling one another an interaction occurs HSC Head Scanning Moving head laterally side to side (often while echolocating) Hit Hit One dolphin contacts another using rostrum or fluke in a 52

quick and aggressive manner ITR Interrupt An interaction between at least 2 dolphins is disrupted by another dolphin JCP Jaw clap Loud popping sound coupled with a fast open and close of mouth LPG Leaping Jumps out of water and reenters head first MNT Mount One dolphin's genital area is thrust onto another dolphin's genital area, or other body part (specify what the mount is directed towards in comments)

MTG Mouthing Dolphin has object in mouth and is manipulating it but not biting down. Usually occurs with sea grass, on another dolphin’s body, etc.

NDG Nudge Dolphin pushes its rostrum on another dolphin’s body

OPM Open mouth Dolphin opens mouth widely, exposing teeth, usually in orientation another dolphin, person, or object. Include in comments the receiver of OPM OTC Orient to camera Dolphin turns head to face camera as it swims by

OTD Orient to dolphin Dolphin turns head towards another dolphin as it passes by OTP Orient to person Dolphin turns head towards a person as it passes by

OTO Orient to object Dolphin turns head towards an object (sea grass, rock, etc.) PDD Push Down One dolphin pushes another down toward the seafloor PUU Push Up One dolphin pushes another up to the surface PET Petting Pectoral fin to pectoral fin rubbing where active movement between pectoral fins is observed PIU Pick up object Dolphin picks up an object with its jaw, dorsal fin, pectoral fin, or fluke PRB Pectoral fin(s) rub One dolphin actively rubs another’s body with it’s pectoral fin PSW Pair swim Dolphin is swimming in same direction with another that is within a (dolphin) body length. ~1.5 meters. (Note ID’s in parenthesis) PSC Pair Swim with Dolphins swimming close while maintaining contact of Contact one body part to another RAM Ram One dolphin hits another's body with its body at fast speed RUB Rubbing A rubbing event where a body part other than the pectoral 53

fin is used to rub against another dolphin SRB Sand Rubbing Dolphin actively rubbing all/part of its body into the san SEX Sexual rubbing Rubbing of one dolphin’s pectoral fins to the genital region TCT Tactile When dolphin briefly contacts (touches) another dolphin, person,. Enter Initiator ID/body part from chart below -- >Receiver ID / receiver body part from chart below if receiver is another dolphin. Ex. Ronnie/H-> Bill/C

Adapted from Dudzinski, 1996; Samuels & Gifford, 1997.

Table A2.

Operational Definitions of Contexts

Code Context Operational Definition

DIO Dolphin interacting Dolphin engages in behavior directed at or interacting with with the surrounding environment, substrate, or object. object/environment DID Dolphin interacting Dolphin engages in behavior directed at or interacting with other with another dolphin(s) dolphin(s) DIH Dolphin interacting Dolphin engages in behavior directed at or interacting with human(s) with a human being. DIA Dolphin interacting Dolphin engages in a behavior in no social context, nor in alone any environmental interaction. Dolphin is alone onscreen. Derived from Kuczaj et al., 2012.

APPENDIX B - Correlation Matrix Tables

Table A1.

Spearman Rank Correlation Matrix for Male DID Coded Items

Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A2.

Spearman’s Rank Correlation Matrix for Female (DID) Coded Items

Items APP AV F BBB BBL BBT CHS FLW GOO GRP GSB HHC HIT HSC ITR JCP MTG OPM OTD PUU PET PRB PSC PSW RAM RUB TCT APP - ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns AV F - - ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns -.68** ns ns ns ns BBB - - - ns ns ns ns ns ns .77** ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns BBL - - - - ns ns ns 1.0** ns ns ns ns ns ns 1.0** ns ns ns ns ns ns ns ns .74** ns ns BBT - - - - - ns ns ns ns ns ns ns ns ns ns .62* ns ns ns .84** ns ns ns ns ns ns CHS ------ns ns ns ns ns .89** ns .73** ns ns .82** ns ns ns ns ns .79** .62* ns ns FLW ------ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns -.63* ns GOO ------ns ns ns ns ns ns 1.0** ns ns ns ns ns ns ns ns .74** ns ns GRP ------ns ns 0.61* ns ns ns ns ns ns ns ns ns ns ns ns ns ns GSB ------ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns

56 HHC ------ns .74** ns ns ns ns ns ns ns ns ns ns .98** ns .61*

HIT ------ns ns ns ns .80** ns ns ns ns ns .82** ns ns ns HSC ------ns .72 ** ns ns ns ns ns ns ns ns ns ns ns ITR ------ns ns .61* ns ns ns ns ns ns .61* ns ns JCP ------ns ns ns ns ns ns ns ns .74** ns ns MTG ------ns ns ns ns ns ns ns ns ns ns OPM ------.66* ns ns .85** ns .88* ns ns ns OTD ------ns .79** .61* ns ns ns ns ns PUU ------.69* ns ns ns ns ns ns PET ------.66* ns ns ns ns .62* PRB ------ns .82** ns ns ns PSC ------ns ns ns ns PSW ------ns .61* ns RAM ------ns .66* RUB ------ns ns TCT ------

Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A3.

Spearman’s Rank Correlation Matrix for Male (DIO) Coded Items

Items APP BBB BBI BBL BBT BTG HSC MTG OPM OTC OTO PIU SRB APP - .57* ns ns ns ns ns ns 0.53* ns ns ns ns BBB - - ns ns ns ns ns ns ns -.57* ns ns ns BBI - - - ns ns .57* ns ns ns ns ns ns ns BBL - - - - ns ns ns ns ns ns ns ns ns BBT - - - - - ns ns ns ns ns ns ns ns BTG ------ns ns ns ns ns ns ns HSC ------ns ns ns ns ns ns MTG ------ns ns ns ns ns OPM ------ns ns ns ns OTC ------ns ns ns OTO ------ns ns PIU ------1.0** SRB ------Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A4.

Spearman’s Rank Correlation Matrix for Female (DIO) Coded Items

Items APP BBB BBL BBT BTG HSC JCP MTG OPM OTC OTO PIU SRB APP - ns ns .98** ns ns ns 0.63* ns ns ns 1.0** ns BBB - - ns ns ns ns ns ns ns ns .74** ns ns BBL - - - ns ns ns .74** ns .68* ns ns ns ns BBT - - - - ns ns .74** .66* ns ns ns .98** ns BTG - - - - - ns ns ns ns ns ns ns ns HSC ------ns ns ns ns ns ns ns JCP ------ns ns ns ns ns ns MTG ------.76** ns ns .63* ns OPM ------ns ns ns ns OTC ------ns ns ns OTO ------ns ns PIU ------ns SRB ------Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A5.

Spearman’s Rank Correlation Matrix for Male (DIH) Coded Items

Items APP AV F BBB BBT EXC FLW HIT HSC MTG OPM OTP RUB TCT APP - ns ns .58* ns ns ns ns ns ns ns ns ns AV F - - ns ns ns ns .61* ns ns ns ns ns ns BBB - - - ns ns ns ns ns ns ns ns ns ns BBT - - - - ns ns ns ns ns ns ns ns ns EXC - - - - - ns ns ns ns ns ns ns ns FLW ------ns ns ns ns ns ns ns HIT ------ns ns ns ns ns ns HSC ------ns ns ns ns ns MTG ------.59* ns ns ns OPM ------ns ns ns OTP ------ns ns RUB ------.57* TCT ------

Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A6.

Spearman’s Rank Correlation Matrix for Female (DIH) Coded Items

Items APP AV F BBL BBT EXC FLW HSC MTG NDG OPM OTP RUB TCT APP - ns ns ns ns ns .74** ns ns .96** ns .65* ns

AV F - - ns ns ns ns ns ns ns ns -.75** ns ns BBL - - - ns ns ns ns ns ns ns ns ns ns BBT - - - - .74** ns .74** 1.0** 1.0** .64* ns .74** EXC - - - - - ns ns .74** .74** ns ns .67* 1.0** FLW ------ns ns ns ns ns ns ns HSC ------ns .74** .86** ns ns ns MTG ------ns ns ns ns .74** NDG ------ns ns ns ns OPM ------ns ns ns OTP ------.65* ns RUB ------.67* TCT ------

Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

Table A7.

Spearman’s Rank Correlation Matrix for Female (DIA) Coded Items

Items BBB BBL BBT HSC OPM BBB - 1.0** ns ns ns BBL - - ns ns ns

BBT - - - ns .68* HSC - - - - ns

OPM - - - - -

Note: *p < 0.05, ** p < 0.001. See Appendix A for behavior code abbreviations.

APPENDIX C - Institutional Animal Care and Use Committee Notice of Committee Action

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