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Studying primate personality in zoos

Citation for published version: Gartner, MC & Weiss, A 2018, 'Studying primate personality in zoos: Implications for the management, welfare and conservation of great apes', International Zoo Yearbook, vol. 52, no. 1, pp. 79-91. https://doi.org/10.1111/izy.12187

Digital Object Identifier (DOI): 10.1111/izy.12187

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Download date: 30. Sep. 2021 STUDYING PERSONALITY IN ZOO-LIVING GREAT APES 1

Int. Zoo Yb. (2018) 52: 1–13 DOI:10.1111/izy.12187

Studying primate personality in zoos: implications for the management, welfare and conservation of great apes M. C. GARTNER1,* & A. WEISS2,3,* 1Philadelphia Zoo, 3400 West Girard Avenue, Philadelphia, Pennsylvania 19104, USA,2Department of Psychology, School of Philosophy, Psychology and Language Sciences, The University of Edinburgh, Edinburgh EH8 9JZ, United Kingdom, and 3Scottish Primate Research Group, United Kingdom E-mail: [email protected], [email protected]

As we face the Anthropocene extinction, many species welfare of the animals in their care. The are threatened or becoming so, and great ape species advantages of studying personality, and are no exception (all are Endangered or Critically Endangered). As humans work to combat this trend, probably other behavioural phenomena, in research on every aspect of the lives of animals is primates that are housed in zoos (rather than vital. One area of research that has the potential to be those in the ﬁeld or laboratory) are described. particularly useful is the study of personality. Zoologi- The authors will discuss how zoos can and cal institutions offer a unique opportunity for research have contributed to the literature about pri- on personality in non-human primates, with knowledgeable staff, consistency in environment, accessibil- mate personality, deliberate about the ways ity of a variety of species and the possibility to have in which such knowledge can facilitate man- large sample sizes to provide generalizability. Here, we agement of great apes in zoos, and consider offer a perspective on how zoos have contributed to how future research might have implications the personality literature, how the personality literature can aid animal management and how much further for welfare and conservation. such research can continue, with implications for both welfare and conservation. STUDIES INTO THE PERSONALITY Key-words: conservation; genetics; great apes; OF PRIMATES personality; primates; research; welfare; zoos. The study of personality in non-human primates has been ongoing since at least the 1930s, although it was only since around INTRODUCTION the 1990s that it attracted the attention of All taxa of great apes are threatened (IUCN, more than a handful of researchers (Whi- 2017) and it is imperative that those who tham & Washburn, 2017). The early work to conserve such species research all research included studies of Chimpanzees aspects of their lives to improve the informa- Pan troglodytes in which personality was tion and resources available to expand our assessed using behavioural measures and knowledge. The goal here is to discuss how ratings (Crawford, 1938; Hebb, 1946a,b, research in zoos has contributed to our 1949). These studies tested whether sub- understanding of the personality of great jects displayed individual differences in apes, and how work on primate personality their behaviour, and in their emotional and can contribute to the goals of zoos and to the cognitive tendencies. The various studies

*The authors contributed equally to this work.

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. 2 CONSERVATION OF GREAT APES assessed whether these differences were and dizygotic twins) have found that consistent across raters and/or stable over genetic differences in personality account time, and whether groups of traits defined for around half of the variation in personal- personality dimensions. Further research ity among individuals (Bouchard & Loeh- included a study of Olive baboons Papio lin, 2001). These twin studies and studies anubis in Nairobi National Park, Kenya of non-twin human siblings have also found (Buirski et al., 1973), a study of Chim- that the non-genetic variation is attributable panzees at Gombe National Park (Buirski to within-family effects (Bouchard & Loeh- et al., 1978) and multiple studies of Rhesus lin, 2001). It is not the characteristics of the macaques Macaca mulatta (Chamove et al., family environment in which one has 1972; Stevenson-Hinde & Zunz, 1978; grown up that make humans differ from Stevenson-Hinde et al., 1980a,b). In addi- one another, but environmental influences tion to testing whether there were stable that have their effect on one child but not individual differences in personality traits another. In other words, whether people and a clustering of traits that signalled the grew up in rich, poor or middle-class presence of underlying dimensions, these households, contributes minimally, if at all, studies examined sex and age differences in to personality differences among individu- personality, and associations between per- als; however, the friends that one child had sonality and rank. that the other child did not have might very The next burst of investigations into the well lead to differences in personality personality of primates, which started dur- (Harris, 1998). ing the 1990s and is still ongoing, included Although the social structures of non- studies of primates in laboratory colonies, human primate species differ from one in the wild and those living in zoos. Non- another and from human social structures, it invasive research in zoos and sanctuaries is possible to conduct quantitative genetic has contributed to our understanding of the studies. The pedigrees of many zoo-housed biological bases of personality and its con- primates are important to maintain and pro- sequences, as we will discuss throughout mote genetic diversity (Glatson, 1986; this article. Basic research tends to be asso- Goossens et al., 2002). By analysing these ciated more with that conducted at primate pedigrees, it is possible to determine the research centres or similar facilities and, extent to which genetic or environmental increasingly, in the field. However, studies influences are responsible for personality of zoo-living primates are growing in num- variation. Pedigrees and other information ber and include work on the genetics of can be used to test the degree to which clo- personality, personality phylogeny, and the sely related individuals are more or less associations between personality and both similar and whether sharing a mother or an physical and psychological health. enclosure is related to how similar individuals are to one another (Kruuk, 2004; Wilson, A. J., et al., 2010). Genetics of personality To date, although there have been few It is possible to examine the degree to genetic studies in zoo populations, the which personality differences between indi- results resemble those found in humans and viduals are attributable to genetic differ- non-primate species. Research on zoo- ences and the degree to which non-genetic housed Chimpanzees (Weiss et al., 2000; influences are responsible for these same Wilson, V. A. D., et al., 2017), orangutans personality differences (Plomin et al., Pongo spp (Adams et al., 2012) and Bono- 2013). Studies of animals bred for higher bos Pan paniscus (Staes et al., 2016) has or lower levels of personality traits (e.g. indicated that personality variation appears anxiety) and studies that compare differ- to be partly related to genetic differences ently related individuals (e.g. monozygotic between individuals and partly related to

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. STUDYING PERSONALITY IN ZOO-LIVING GREAT APES 3 the influences of environmental effects that and multiple dimensions in another. Phylo- operate at the within-zoo or within-family genetic studies have been used to help clar- level. At the time of writing, no comparable ify the evolution of personality in primates. study has been conducted on gorillas Gor- Such studies have also provided a clearer illa spp. understanding of personality evolution in Some genetic studies involve the attempt humans, the following example of which is to find genes that are related to specific per- informative. Human personality varies sonality traits. In primates, these studies are along five dimensions: Neuroticism, presently limited to tests of whether ‘candi- Extraversion, Openness to Experience, date genes’ are related to personality varia- Agreeableness and Conscientiousness (Dig- tion, thus resembling early attempts to find man, 1990). Several explanations for why genes for human personality traits (e.g. Reif human personality is constituted by these & Lesch, 2003). Studies of Chimpanzees dimensions have been put forward. How- living at Yerkes National Primate Research ever, many of these explanations are based Center (Atlanta, GA, USA) (Hopkins et al., on scenarios that are unique to humans or, 2012; Latzman et al., 2015), and those liv- at the very least, unique to social species. ing mostly in zoos, research centres and a Searching for similar personality dimen- sanctuary in Japan, amounting to 129 sions in species that are unlikely to encoun- Chimpanzees including 19 that lived at a ter these evolutionary scenarios is a ‘strong sanctuary in Guinea (Wilson, V. A. D., test’,asdefined by Platt (1964), of the et al., 2017), found evidence that versions plausibility of any such explanation (Weiss, of a gene for receptors for the hormone 2018). For example, Extraversion and vasopressin are associated with the person- Agreeableness are often linked to evolution- ality dimension Conscientiousness, which ary scenarios partly or wholly centring on describes how tame and predictable individ- human sociality and altruism, respectively uals are [see Staes et al. (2016) for a simi- (e.g. Nettle, 2006). The fact that similar lar finding in Bonobos]. However, the dimensions emerge in a semi-solitary great effects of single genes are very small, typi- ape (orangutans), suggests that these dimen- cally accounting for <1% of trait variation. sions reflect the workings of other selective Therefore, these studies are rare in non- pressures (Weiss & King, 2015). human primates and in humans the findings often do not replicate (Munafo et al., Association between personality and 2003). In response to the growing aware- physical and psychological health ness that many earlier findings may have been false positives, molecular genetic stud- Studying great apes in zoos has provided ies of human personality traits have been insight into the associations between person- turning towards studies that involve exam- ality and psychological and physical well- ining the effects of a vast number of genes being. A study of 128 Chimpanzees from in samples, often comprising 100 000 or 13 different zoos found that individuals more participants. rated higher in subjective well-being had personality profiles that characterized them as lower in traits related to Neuroticism Personality phylogeny (high Dominance in this case) and higher in The study of personality phylogeny answers Extraversion (King, J. E., & Landau, 2003). questions about why individuals of one spe- In humans, the personality dimensions cies can be classified along a specific per- Extraversion and Neuroticism are related to sonality dimension whereas those of higher and lower subjective well-being, another species cannot. A related question respectively (DeNeve & Cooper, 1998; is why some personality differences are Steel et al., 2008). Another study of Chim- described by one dimension in one species panzees found that the association between

Dominance and subjective well-being was patients – or animals – and health-care attributable to common genetic effects practitioners – or vets. (Weiss et al., 2002). It would appear that the genes associated with Dominance differ- BEHAVIOUR, MANAGEMENT AND ences were also associated with subjective CONSERVATION well-being differences. Later studies of primates in zoos and other settings have found Primates are the most studied animals in similar associations between personality and zoos (Melfi, 2009). The largest focus of this subjective well-being (Weiss et al., 2006, research in British and Irish zoos is on 2011; Robinson et al., 2016). Likewise, the social behaviour, while in American zoos genetic association between these personal- the focus is on reproduction and endocrinol- ity dimensions and subjective well-being ogy (Melfi, 2005). In Europe, the United has been found in a pedigree-based study of States and Japan there have been a large zoo-living orangutans (Adams et al., 2012), number of studies on primate cognition as well as in human twin and sibling studies (Hopper, 2017). However, very little (Weiss et al., 2008; Hahn et al., 2013), and research is carried out on personality, and in a molecular genetic study of humans even less on the link between personality (Weiss et al., 2016). and behaviour (Stoinski et al., 2004). More- The links between personality and physi- over, methodological studies, such as vali- cal well-being have not been well studied dating personality-trait ratings with in zoo research, although they are excep- behavioural observations, are often the tionally well-documented in humans (Deary focus of this work. The validity of one type et al., 2010). One exception is a study car- of assessment versus another has been cov- ried out in the 1990s into Gorilla Gorilla ered elsewhere, with trait ratings shown to gorilla personality, assessing 298 captive be just as, if not more, reliable than beha- individuals over 1 year of age to create a vioural observations (e.g. Vazire et al., ‘Gorilla Behavior Index’ using behaviou- 2007); therefore, links between the two have rally defined adjectives (Gold & Maple, been found and tend to be evident. For 1994). Following common factor analysis, example, gorilla Dominance is related to four factors were identified: Extroverted received and given displacement (negative (henceforth ‘Extraversion’ and ‘Extra- and positive, respectively) (Kuhar et al., verted’), Dominant, Fearful and Under- 2006; Schaefer & Steklis, 2014); and standing. In a follow-up study carried out Extraversion/Agreeableness is related to more than 18 years later, it was found that affiliative, grooming, playing, approach and Gorillas rated higher on Extraversion lived touching behaviours (Schaefer & Steklis, longer lives than their more introverted 2014). Similarly, Chimpanzee Extraversion counterparts, an effect that could not be is related to affiliative behaviour (Pederson explained by demographic information or et al., 2005; Massen & Koski, 2014). A husbandry practices (Weiss et al., 2013). relationship has also been shown between Knowing this type of information could Chimpanzee Dominance and agonistic beha- inform current veterinary care or end-of-life viours (a positive relationship) and submis- decisions. Suggestions on how to use per- sive behaviours (a negative relationship) sonality in care have been made (Deary (Freeman et al., 2013). In the same study a et al., 2010) and most of these are also relationship was also found between applicable to animals (Gartner & Weiss, Extraversion and contact aggression. This 2013), including heightened surveillance for type of research could have a direct impact those with traits related to earlier mortality; on management decisions. For example, the development of specific, individual gorillas housed in solitary situations rated intervention strategies; targeted drug treat- lower on the Understanding factor (Kuhar ments; and improved relationships between et al., 2006). Although this result needs to

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. STUDYING PERSONALITY IN ZOO-LIVING GREAT APES 5 be validated, if it were the case, and Under- husbandry to align with personality differ- standing was predictive of a need for soli- ences has been shown to benefit breeding tary housing, planning for housing in Giant pandas Ailuropoda melanoleuca provision could be made easier, both within (Powell & Svoke, 2008). Using measure- single zoos and across zoos. This could lead ments such as faecal corticosteroids and to a reduction of aggressive encounters, behavioural observations can establish because gorillas rated lower for Understand- parameters for well-being that facilitate ing were also more likely to engage in non- improved reproductive success, as has been contact aggression (Kuhar et al., 2006). It found in Clouded leopards Neofelis nebu- has been suggested that gorilla groups losa (Wielebnowski et al., 2002). should be formed when the apes are young Primate behaviour in zoos in response to for the best outcomes (Stoinski et al., exposure to humans, typically unknown 2004), so it is vital to understand any age- visitors rather than familiar keepers, may related differences in personality, but this is also be impacted by personality. For exam- not always possible in zoos (see Huskisson ple, solitary, irritable and aggressive Diana & Chism, 2018). Knowing that silverback monkeys Cercopithecus diana diana gorillas rated highly on the personality demonstrate increased abnormal behaviour dimension Understanding are more accept- during peak visitor times, while active, ing of new members into their troop (Stoin- playful and excitable individuals show spe- ski et al., 2004) could be a vital piece of cies-typical behaviour, including play (Bar- information that facilitates successful group- low et al., 2007). For zoos, this information ings. Longitudinal studies are particularly could be vital not only to animal welfare important for assessing any links between but also for visitor satisfaction, as visitors personality and age. For example, in Chim- tend to prefer naturalistic exhibits that pro- panzees, Extraversion and Openness decline mote activity (Ryan & Saward, 2004; Fer- with age, while Agreeableness and Consci- nandez et al., 2009). Gorillas show more entiousness increase (King, J. E., et al., relaxed behaviours during low visitor den- 2008). In orangutans, Agreeableness decli- sity, and higher rates of aggression, auto- nes with age, and while Extraversion also grooming and stereotypies during high visi- decreases as orangutans age, it does so dif- tor density [Wells, 2005; see Ross et al. ferently from Chimpanzees (Weiss & King, (2007) and Wells (2007) for discussion of 2015). Zoos are often in the position of hav- these results]. Changes in group structure, ing to move individuals within groups of such as the birth of an infant, may also animals, which can pose risks to both the have an effect on how gorillas react to visi- individuals involved and their caretakers tors (e.g. Collins & Marples, 2016). Visitor (Powell, 2010). Personality is another tool density is not a stressor for all individuals zoos can use to decrease risk and increase (Hosey, 2000), and crowd size may or may success when making decisions about form- not have an effect on behaviour in various ing new groups of great apes. species in zoos (Ross et al., 2007; Bonnie Personality can also affect other areas of et al., 2016; Jones et al., 2016; Martin, animal management; for example, personal- R. A., & Melfi, 2016; Polgar et al., 2017). ity studies have shown that captive breed- Using available knowledge about individual ing can be facilitated in a number of ways. personality to schedule exposure to visitors In felids, providing secluded enclosures and could increase welfare and decrease ample hiding spaces for animals that rate unwanted behaviours in primates in zoos. higher on tense or fearful personality fac- Environmental enrichment is a common tors can improve breeding success, as was tool that is used to increase both the physi- found with Cheetahs Acinonyx jubatus cal and psychological well-being of animals (Wielebnowski, 1999). Similarly, making in zoos; however, the efficacy of the enrich- species-specific changes in enclosures and ment provided may be affected by

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. 6 CONSERVATION OF GREAT APES personality (e.g. Massen et al., 2013). A While personality has the potential to study of Snow leopards Panthera uncia predict behaviour, it is possibly also influ- suggested that personality may impact enced by environment. Different types of enrichment choices made by zoos (Gartner rearing, including group size, group compo- & Powell, 2012). Because enrichment has sition and experience of other infants within not been entirely successful in decreasing the group, may all have a different effect unwanted behaviours (Mason et al., 2007), upon individuals. For instance, Chim- it would be useful to carry out more studies panzees that are reared in larger groups to assess the impact of enrichment and the (≥ 7 individuals) are rated more highly on different methodologies used for such stud- positive personality traits (e.g. playful) than ies. By understanding individual prefer- those reared in smaller groups (≤ 3 individ- ences that might have an impact on the uals), but also are rated as more Irritable effectiveness of enrichment, a more focused and Excitable/Slow (Murray, 1998). How- provision can be made to improve welfare, ever, a later study by Martin, J. E. (2005) as well as possibly counteract unwanted found no such associations, so more work behaviours (e.g. pacing). In addition, an on this subject is needed. individual’s response to an enrichment item Finally, zoos are one of the largest sup- itself may be used as a metric for quantify- porters of conservation, both financially and ing personality characteristics (Gartner & with expertise (Barongi et al., 2015). Per- Powell, 2012; Massen et al., 2013). sonality can affect strategies for survival Enrichment can be used to challenge ani- (Watters & Meehan, 2007), as well as rein- mals mentally and physically (Shepherdson, troduction efforts (Bremner-Harrison et al., 1998), and can be conceived of on both the 2004). Although relatively few zoo animals species and individual level (Mellen & are reintroduced to the wild, some projects Sevenich MacPhee, 2001). While little direct have been initiated and personality should be research has been carried out on personality a consideration (e.g. Cocks & Bullo, 2008; and welfare, one study with Chimpanzees King, T., & Courage, 2008). Some of these found that welfare measures correlate with projects have brought back species from near subjective well-being measures, and that extinction (e.g. Black-footed ferret Mustela higher Extraversion and lower Neuroticism nigripes, California condor Gymnogyps cali- were related to higher ratings on the com- fornianus, Golden lion tamarin Leontopithe- bined welfare/subjective well-being measure cus rosalia, the Karner Blue butterfly (Robinson et al., 2017). Understanding an Lycaeides melissa samuelis, Oregon spotted individual’s personality can help keepers to frog Rana pretiosa, Palila Loxioides bailleui, create a proactive (rather than reactive) envi- Red wolf Canis rufus and Wyoming toad ronment for zoo animals (Mellen & Seve- Anaxyrus baxteri) (see examples in Dobson nich MacPhee, 2001). & Lyles, 2000; Walters et al., 2010). Studies Great ape cognition and its relationship carried out in zoos may inform work that is to personality is a growing field of study. carried out in the wild and vice versa. For Chimpanzees rated higher on Openness are example, one study found a similar personal- more willing to participate in research stud- ity structure in zoo and sanctuary Chim- ies (Herrelko et al., 2012). Furthermore, panzees (King, J. E., et al., 2005), indicating those rated higher on Neuroticism per- that captivity may not affect the way that formed more self-directed behaviours dur- personality traits cluster together. In that ing the study (Herrelko et al., 2012). This study, the Chimpanzees at the sanctuary has implications for animal management, (wild born and rescued from a variety of where animals rated higher on Openness non-normal situations) were being condi- could be chosen first for training, which tioned for reintroduction into the wild. may provide the more reluctant animals Studies carried out at zoos could inform with positive role models. managers of how animals should be

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. STUDYING PERSONALITY IN ZOO-LIVING GREAT APES 7 grouped for release, how they may react to numerous studies of single zoos, which are release and in what stages release should valuable but not deﬁnitive or generalizable, occur. By using zoological records, such as narrowing their usefulness. To counteract information on pedigree, researchers can these limitations, many researchers recom- take this one step further to look at the mend multi-zoo studies (Swaisgood & genetics of natural selection and adaptation Shepherdson, 2005; Whitham & Wieleb- in captivity (Pelletier et al., 2009). This nowski, 2013). However, these too come could help zoos to limit contemporary evo- with challenges. Including more than one lution in captivity, which may affect future zoo in a research project requires much reintroductions to the wild, as well as such time and effort to establish and maintain health outcomes as breeding success (Pel- professional relationships, as well as ensur- letier et al., 2009). ing the data collected from each institution The results of research into personality is of the same quality and detail. Depend- and behaviour of wild animals in zoos is ing on the type of study, this could be rela- promising, and should be encouraged. If tively easy. For example, a pivotal study of personality allows for the prediction of personality and longevity in Western low- behaviour, then zoo-animal management land gorillas included 43 zoos but the data can be improved once such knowledge is came from one database, all of the zoos available. The types of studies described involved were from countries speaking the above could be invaluable in animal man- same language and one of the authors agement, as personality assessment would worked at one of the participating zoos take some of the guesswork out of manage- (Weiss et al., 2013). However, things ment decisions, which has the potential to become more difﬁcult if data need to be increase psychological and physical welfare collected by a researcher present at a zoo for animals in zoos. (e.g. behavioural data) or if the zoos These examples reveal some possibilities involved are not all from countries speaking of the implications for animal management the same language (e.g. involving transla- and, although zoos already play a role in tions of test materials). Data collection from learning about animal behaviour, there is more than one zoo could then be hindered still a wealth of work that could be done. by monetary and time constraints, as well For example, studies could be carried out as lack of staff or a lack of interest. Anec- in zoos to investigate how a better under- dotally, experience demonstrates that per- standing of individual personality could sonality studies still seem to face these make it possible to predict behaviour in pri- problems in zoos, despite growing literature mates. Research on human personality and showing their importance. However, the behaviour is vast and varied, and can help Association of Zoos and Aquariums (AZA) zoos to begin to understand and predict has increased its focus on research, recently how the animals in their care may react creating a Research and Technology Com- individually to different situations, as men- mittee. AZA expects its members to con- tioned above. However, adaptations to duct or facilitate research, and provides study design are vital. Researchers focusing some grant funding for such projects. In on humans often have access to larger sam- addition, new technological projects, such ple sizes, allowing for generalizations about as ZooMonitor, a Web application designed populations; however, researchers in zoos for easier and more reliable data collection, frequently do not have large numbers of is available to zoos at little to no cost animals to study. For example, for great (https://zoomonitor.org: Lincoln Park Zoo, apes in a single zoo there are usually only Chicago, IL, USA). This type of technology a small number of individuals and they are could facilitate multi-zoo studies with only often housed together. This leads to minimal training required.

ecological validity. In addition, zoo animals THE FUTURE OF ZOOS IN may be likely to demonstrate better examples PERSONALITY RESEARCH of species behaviour (i.e. zoos encourage Research carried out at zoos has led to sev- expressions of natural behaviour) than indi- eral advances in our understanding of per- viduals housed in laboratories, where ani- sonality, its antecedents, and its mals may be subject to conditions that do consequential effects in non-human pri- not encourage such behaviours (e.g. single mates, humans (e.g. the evolution of person- housing of social species). ality) and other animals. To continue this The study of personality and other beha- theme and foster high-quality research on viours in zoos also benefits from the fact that other topics in primates and other species in each enclosure and each zoo is a micro-envir- zoos, we conclude by outlining some reasons onment. This variation can be harnessed in why zoos are a good resource for research on quasi-experimental studies (Cook & Camp- personality and behavioural phenomena. bell, 1979). For example, some studies have Finally, some suggestions are offered to the examined whether seeing and/or hearing visi- wider community of zoos that will help make tors influences the behaviours of animals (i.e. this research environment even better. a zoo effect) (Hosey, 2000), or how being clo- As mentioned earlier, one advantage of sely related to other individuals in an enclo- carrying out research in zoos is that by coor- sure influences behaviour (i.e. an enclosure dinating data collection across multiple zoos, effect) (Price & Stoinski, 2007). These effects it is possible to have large sample sizes, even are likely not independent, but analytic meth- of highly threatened species. For example, ods, such as mixed-effects modelling (Singer, our study of Western lowland gorilla person- 1998), can take this nesting of effects into ality and longevity involved 283 gorillas at account. These sorts of studies would be the 42 zoos (Weiss et al., 2013). These large flip side of field experiments, such as those sample sizes translate into greater statistical described by Matsuzawa (2011). power and reproducible findings (Cohen, Observations of animal personality and 1992). It may be possible to leverage the behaviour benefit from zoo-based studies findings from genome-wide association stud- because the staff at zoos are incredibly ies, and launch the next generation of molec- knowledgeable about the animals in their ular genetic studies of primate personality. care. This has been borne out by studies that Another advantage of studying animals in have evaluated the reliability of staff ratings zoos is that these environments make it pos- of animal well-being, personality and wel- sible to achieve a balance of control and eco- fare (e.g. Robinson et al., 2017). The ratings logical validity (Petrinovich, 1979). Control zoo staff provide during such studies have is associated with experimental laboratory led to real insights into personality evolution research, and refers to designs that make it (e.g. King, J. E., & Weiss, 2011; Weiss, possible to isolate stimuli (or combinations 2018). Detailed descriptions of animal beha- of stimuli) that cause an effect and to keep viour can be found in the early ethological factors extraneous to the research question to literature (e.g. Tinbergen, 1959). Researchers a minimum (Kerlinger, 1964). The zoo set- can utilize knowledge about common, rare ting provides control by complying with reg- or unusual behaviours, and the range of ulations for enclosure sizes, the provision of behaviours that staff have witnessed over enrichment, diet and procedures that ensure long periods of time, providing a prime the health of the animals, keeping the major source for testable hypotheses. In addition, aspects in the lives of animals constant. By zoos house a diverse range of species, which mimicking the natural and social environ- means a large amount of research could be ments of the species in their care (e.g. form- carried out to answer a variety of questions. ing social groups that resemble those of wild While there may be some effects of contem- counterparts) zoos maintain some degree of porary evolution taking place, zoo animals

Int. Zoo Yb. (2018) 52: 1–13 © 2018 The Authors. International Zoo Yearbook published by John Wiley & Sons Ltd on behalf of Zoological Society of London. STUDYING PERSONALITY IN ZOO-LIVING GREAT APES 9 are specifically bred to conserve genetic appropriate individuals and facilities for diversity, a factor that allows for possible focus and/or investigation of the genetic or comparisons to wild counterparts, which environmental bases of behaviour. One good may have an effect on future conservation example of this is the Great Ape Information efforts. Network (GAIN: https://shigen.nig.ac.jp/ga in). This freely accessible website offers detailed information about the Chimpanzees, ENHANCING THE CONTRIBUTION orangutans, Gorillas, Bonobos and gibbons OF ZOOS TO SCIENCE at Japanese zoos and research facilities, Zoos are outstanding resources for personal- including personality profiles for the Chim- ity research because they provide accessibil- panzees. Although only accessible to mem- ity to multiple related species, which is bers, the Zoo Information Management crucial for comparative research. However, System (ZIMS) of Species360 (Blooming- there are ways in which the scientific contri- ton, MN, USA) also provides a rich source butions of zoos can enhance the study of of animal data. personality and other research areas. We Having one straightforward, unambigu- invite readers to contact the authors if they ous electronic system in place that allows have other suggestions or recommendations. for approval of proposed multi-zoo research from one source as well as feedback on rejections of project requests, would ease Standardized questionnaires communication and other logistical prob- Using questionnaires to study personality lems that researchers face when trying to (or behaviour) of zoo animals makes it pos- set up such studies. sible to measure traits using a standardized format of data collection. This standardiza- tion is essential when collecting large CONCLUSION amounts of information. The ChimpanZoo As we have shown, zoos provide an invalu- programme of the Jane Goodall Institute able resource for personality research. Local (http://www.chimpanzoo.org) showed con- expertise and facilities may vary, and some siderable promise in this aspect of data col- zoos are better suited for learning studies lection. Chicago Zoological Society’s Center for the Science of Animal Care and and others for personality research. How- ever, well-planned and relevant studies into Welfare (Brookfield, IL, USA) has devel- ® personality, behaviour and cognition carried oped WelfareTrak , a welfare-monitoring out in zoos can contribute to the literature tool that utilizes the knowledge, skills and and provide a solid basis for animal-man- expertise of keepers (https://www.welfaretra agement protocols. As available knowledge k.org). At the time of writing, keeper rat- ® increases a corresponding improvement in ings in WelfareTrak are being validated the welfare, well-being and conservation of against behavioural and hormonal data in wild animals should also occur. Chimpanzees. These sorts of projects could also result in a standard core ethogram and ACKNOWLEDGEMENTS a core set of behavioural tests for species The authors would like to thank Dr Charlotte MacDon- that could be used in behavioural studies. ald, Director of Conservation and Living Collections, Royal Zoological Society of Scotland, for her valued input on this work. A.W. also thanks Virginia Landau Data accessibility from whom he learned a lot about zoos, chimpanzees, and chimpanzees living in zoos. A way to enhance personality and behaviour research would be to make basic demo- REFERENCES graphic and relatedness data openly avail- ADAMS, M. J., KING,J.E.&WEISS, A. (2012): The able. This would help researchers to choose majority of genetic variation in orangutan personality

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