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Simple Summary: A survey was sent to zoos, research facilities, and sanctuaries which housed chimpanzees. The behavioral profiles of 1122 chimpanzees were collected for this survey. Data collected included information about the animals' age, sex, social group size, rearing history, and enclosure as well as information about each animal's behavior. Each respondent was asked to indicate if certain behaviors had been observed in each chimpanzee over the prior two years. Species typical behaviors (STBs) were queried, including copulation, tool-use, nest-building, and social grooming. Tool-use was reported to be present for 94.3% of the sample, active grooming for 85.7%, copulation for 68.3% and nest-building for 58.9%. Male chimpanzees who were not reared by their conspecific mother were most likely to have deficits in STBs, and female chimpanzees who were mother-reared were generally the most likely to engage in STBs. A survey was sent to zoos, research facilities, and sanctuaries which housed chimpanzees. Data collected included information about 1122 chimpanzees' age, sex, social group-size, rearing history, and enclosure. Respondents were also asked to indicate if certain behaviors had been observed in each chimpanzee over the prior two years. Species- typical behaviors (STBs) were queried, including copulation, tool-use, nest-building, and social grooming. Tool-use was reported present for 94.3% of the sample (n = 982), active social grooming for 85.7% (n = 1121), copulation for 68.3% (n = 863) and nest-building for 58.9% (n = 982). Of the subjects for whom we had data regarding all four STBs (n = 860), 45.6% were reported to engage in all four. Logistic regression analyses using forward Wald criteria were conducted to determine the best model for each STB based on the predictors of age, sex, rearing history, group-size, facility-type, and a sex-by-rearing interaction. The best model for copulation (χ2(6) = 124.62, p < 0.001) included rearing, group-size, facility-type, and the sex-by-rearing interaction. Chimpanzees were more likely to copulate if they were mother-reared, in larger groups, living in research facilities, and, if not mother-reared (NOTMR), more likely to copulate if they were female. The best model for tool-use retained the predictors of age category, facility-type, and sex-by-rearing (χ2(5) = 55.78, p < 0.001). Chimpanzees were more likely to use tools if they were adult, living in research facilities, and if NOTMR, were female. The best model for nest-building included facility-type and rearing (χ2(3) = 205.71, p < 0.001). Chimpanzees were more likely to build nests if they were MR and if they were living in zoos or in sanctuaries. The best model for active social grooming retained the predictors of age, sex, rearing, and type of facility (χ2(6) = 102.15, p < 0.001). Chimpanzees were more likely to engage in active social grooming if they were immature, female, mother-reared, and living in zoos. This research provides a basic behavioral profile for many chimpanzees living under human care in the United States and allows us to determine potential methods for improving the welfare of these and future chimpanzees in this population. [ABSTRACT FROM AUTHOR]

Simple Summary: To improve the lives of chimpanzees living in managed care, it is important to understand why their lives have ended. Previous efforts to document the causes of death for chimpanzees living in research facilities have been useful; however, interpretations need to consider the relatively small number of facilities assessed, the recency of those evaluations, and the possibility that mortality rates were affected by experimental interventions at these sites. Here, the causes of death of 224 chimpanzees at 42 accredited zoos over a 25-year period were analyzed. Most of the chimpanzees over 1 month of age died from causes associated with degenerative diseases (50%), infection (26%), and trauma (15%). Causes of fatal trauma ranged from aggression from conspecifics, the outcomes of exhibit escapes, or accidental drowning. The number of accidental deaths has decreased in the past decade, likely as a result of advances in exhibit design and management. Cardiopulmonary problems have long been known to be prevalent within the chimpanzee population, and they remain a major contributor to death for both sexes in this population. Understanding these findings provides an opportunity to improve the care and management of captive chimpanzees. Understanding causes of death allows adjustment of health management strategies for animals in managed care. From 224 documented chimpanzee deaths occurring from 1995 to 2019 in 42 accredited U.S. zoos, post-mortem records and necropsy reports were analyzed for the primary cause of death, which were available for 214 individuals. In total, 37 cases of stillbirth and neonatal deaths were assessed (16.5%); however, the focus was otherwise placed on the remaining 177 cases in which the death occurred in individuals aged greater than 1 month. There were no sex-related differences in etiology; however, age variation in the cause of death was statistically significant (p < 0.001). Elderly (35 years and older) chimpanzees tended to die of intrinsic, often degenerative, etiologies, whereas infants, juveniles, and adolescents (less than 15 years) were more likely to be involved in fatal trauma. Overall, there were 27 deaths (15.3% of all post-neonatal deaths) related to trauma and 13 of these were directly or indirectly related to conspecific aggression. Understanding causes of mortality and the interrelation with management can benefit managed populations of chimpanzees. [ABSTRACT FROM AUTHOR]

It is important to those managing Japanese macaques (Macaca fuscata) in captive settings to understand predictors of wounding. While studies have demonstrated that season (breeding or nonbreeding) and sex predict rates of wounding received by zoo‐housed Japanese macaques, we investigated whether individual differences in personality ratings also might explain some of the observed interindividual variance in wounding. Such patterns were previously observed in rhesus macaques (M. mulatta), such that individuals rated higher on Anxiety and Confidence received greater wounding. Here, we collected wounding data over 24 months on 48 Japanese macaques from eight AZA‐accredited zoos. Each macaque was also rated by keepers using a 26‐item personality questionnaire. Principle components analysis of these ratings revealed four personality components: Openness, Friendliness, Dominance, and Anxiety/Reactivity. The model with the best fit revealed an interaction effect between season (breeding vs. nonbreeding) and the personality component Friendliness, such that individuals rated higher on Friendliness incurred fewer wounds in the nonbreeding season. The second‐best model revealed both a main effect of the season as well as an interaction effect between season and Openness, such that macaques rated higher in Openness received more wounds in the nonbreeding season than those rated lower in Openness. Thus, as with rhesus macaques, personality mediated wounding receipt rate in Japanese macaques, although different personality components explained interindividual variance in wounding for these two species. These differences likely reflect species differences in behavior and personality structure, as well as the influence of differing management practices, highlighting the importance of species‐specific approaches for captive primate care and welfare. This study provides further support for understanding primate personality to create individualized strategies for their care. Highlights: Predictors of the wounding receipt rate of 48 zoo‐housed macaques living in eight accredited zoos were examined.Wounding rates were mediated by interaction effects between the macaques' personality ratings and season.The macaques received more wounds during the breeding season, as compared to the nonbreeding season.Higher ratings on Friendliness were associated with the receipt of significantly fewer wounds received, but only in the nonbreeding season.Higher ratings on Openness were associated with the receipt of significantly more wounds received, but only in the nonbreeding season. [ABSTRACT FROM AUTHOR]

At zoos, and some sanctuaries, members of the public can observe the resident animals. Examining the characteristics and consequences of this type of human–animal encounter is important to understand public education and engagement as well as animal behavior and welfare. Zoos typically have a large and consistent visitor presence, and researchers report mixed findings regarding the effects of the visiting public on the behavior of resident primates. In contrast, public visitation at sanctuaries more often occurs sporadically and on a relatively small scale, as compared with zoos, and typically via organized tours or educational events. Owing to these differences, it is necessary to explore the effects of public programs on animals in sanctuary settings in addition to the more comprehensive efforts studying such influences in zoos. Therefore, we observed four groups of sanctuary chimpanzees (Pan troglodytes) at Chimp Haven (USA) over one year, including opportunistic observations during public programs. These scheduled, but infrequent, educational events offered visitors the possibility to view chimpanzees in outdoor enclosures and sometimes included staff-led small tours and food and enrichment provision to the chimpanzees. Our aim was to determine whether the 50 chimpanzees' behavior differed when public programs were offered at the sanctuary compared with "baseline" periods. It was found that during these programs chimpanzees spent more time in outdoor enclosures (GLMM: est. = 1.559, SE = 0.309, Z = 5.04, p < 0.001) and increased time feeding (GLMM: est. = 0.754, SE = 0.356, Z = 2.11, p = 0.034) and locomoting (GLMM: est. = 0.887, SE = 0.197, Z = 4.50, p < 0.001) compared with times when public programs were not ongoing. We rarely observed agonistic and abnormal behaviors, potential metrics of welfare, regardless of whether public programs were ongoing. Abnormal behaviors occurred too infrequently for statistical analysis. While the chimpanzees showed some differences in their behavioral repertoire during the public programs, such changes do not suggest that their welfare was compromised as a result of these activities. [ABSTRACT FROM AUTHOR]

Japanese macaque societies are characterized by frequent intragroup conflict both in free‐ranging and zoo‐housed conditions. In zoos, understanding the factors that contribute to wounding is of interest because this knowledge can aid in proactive husbandry and management planning that can minimize the negative impacts wounding can have on individual welfare. This study sought to determine whether the variables sex, season and age predicted wounding rates. Data were collected for 24 months on 119 Japanese macaques living in 10 zoos, and we analyzed the contribution of variables using generalized linear mixed models. A total of 1,007 wounds were reported, and the best model included the interaction between sex and season. Follow‐up analyses revealed that females incurred more wounds than males, and this sex difference was more pronounced during the breeding compared to the nonbreeding season. On average, individuals received 4.67 (±SEM: 0.55) wounds per year and 77.31% of the population incurred at least one wound in the study period. The majority of wounds were superficial and did not require veterinary intervention. Wound locations were not randomly distributed across body regions and were most often reported on the face. Finally, macaques living in larger social groups experienced more wounds, on average. This study represents the first quantification of wounding in this species and may provide insight to help inform husbandry and management strategies in zoos. HIGHLIGHTS: Analysis of wounding in 119 zoo‐housed Japanese macaques revealed that females were wounded more than males and this difference was greater in the breeding season.Most wounds were superficial and the face was the body region most frequently wounded. [ABSTRACT FROM AUTHOR]

In the past few decades, there has been an increase in the number of zoo‐based touchscreen studies of animal cognition around the world. Such studies have contributed to the field of comparative cognition despite the fact research has only been performed at a relatively small number of institutions and with a narrow range of species. Nonetheless, zoo‐based touchscreen studies are increasingly recognized as both having the potential to be enriching for captive animals by providing them with opportunities for choice, as well as potentially being a tool with which to measure changes in welfare. Zoo‐based touchscreen research on public display also has the potential to impact zoo visitors; encouraging them not only learn more about the cognitive abilities of animals, but also potentially promoting increased respect for these species. Given the lack of a comprehensive review of this scope of specialized research, and the broad potential impacts on animals and programs, here we discuss the history, implementation, and potential outcomes of touchscreen research in zoo settings. [ABSTRACT FROM AUTHOR]

Video cameras are increasingly being used to monitor captive animals in zoo, laboratory, and agricultural settings. This technology may also be useful in sanctuaries with large and/or complex enclosures. However, the cost of camera equipment and a lack of formal evaluations regarding the use of cameras in sanctuary settings make it challenging for facilities to decide whether and how to implement this technology. To address this, we evaluated the feasibility of using a video camera system to monitor chimpanzees at Chimp Haven. We viewed a group of resident chimpanzees in a large forested enclosure and compared observations collected in person and with remote video cameras. We found that via camera, the observer viewed fewer chimpanzees in some outdoor locations (GLMM post hoc test: est. = 1.4503, SE = 0.1457, Z = 9.951, p < 0.001) and identified a lower proportion of chimpanzees (GLMM post hoc test: est. = −2.17914, SE = 0.08490, Z = −25.666, p < 0.001) compared to in‐person observations. However, the observer could view the 2 ha enclosure 15 times faster by camera compared to in person. In addition to these results, we provide recommendations to animal facilities considering the installation of a video camera system. Despite some limitations of remote monitoring, we posit that there are substantial benefits of using camera systems in sanctuaries to facilitate animal care and observational research. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the potential for a behavioral research study, designed to evaluate chimpanzee decision-making behavior, to also encourage increased activity in a group of zoo-housed chimpanzees. For the behavioral study, the chimpanzees had to carry tokens to different locations such that they always had to travel farther to obtain a more-preferred reward. We recorded the distance travelled by each subject in each of the three phases of the 15-month study. By the final phase, the chimpanzees' rate of travel during test sessions was significantly higher compared to their baseline activity. Importantly, the chimpanzees' increase in locomotion was not dependent on their participation in the study; rate of travel was not correlated with number of tokens exchanged. However, the chimpanzees' activity returned to baseline within 2 hr of the 30-min test sessions. This study emphasizes the role that research can have in providing enrichment, the importance for long-term enrichment plans, and the essential need to evaluate the impact of research on animal participants, just as we evaluate the efficacy of enrichment strategies. Zoo Biol. 35:293-297, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In North American zoos, male gorillas are often housed in all-male (bachelor) groups to provide socialization for males not managed in breeding groups. These groups exhibit long-term cohesion and stability and males in bachelor groups are no more aggressive than males in mixed-sex groups. Previous studies have shown that aggression in male gorillas is more directly related to age rather than group type, with young silverbacks (YSB; males 14-20 years of age) having higher rates of aggressive behavior than males of other age classes. Despite this, anecdotal reports have persisted that bachelor groups have higher wounding rates than mixed-sex groups. To assess wounding in zoo-housed gorillas, all instances of wounding across 28 zoos (180 gorillas, 45 social groups) were recorded over a 26 months period via a standardized data sheet. Similar to previous reports, we found age to be an important determinant in wounding. Bachelor groups that contained YSB's had significantly more wounds than bachelor groups without YSB's ( U = 14.0, z = −2.193, P = 0.029). There was no difference in wounding rates between mixed-sex and bachelor groups without YSB's ( U = 69.5, z = −0.411, P = 0.689). These data further demonstrate the importance of behavioral management of YSB's in zoos and the viability of bachelor groups as a long-term housing solution for male gorillas. Zoo Biol. 34:296-304, 2015. © 2015 Wiley Periodicals Inc. [ABSTRACT FROM AUTHOR]

Outdoor access is often cited as a critical component of appropriate housing for great apes in captivity, and although studies have shown that offering primates choices can improve welfare, choice to access specific areas has been empirically neglected. Behavioral data were collected on chimpanzees and gorillas housed in naturalistic enclosures while (a) restricted to an indoor enclosure and (b) permitted free access to an adjacent outdoor area. To isolate the factor of choice, only the sessions in which apes remained indoors were compared. With choice, chimpanzees showed more frequent social,F(1, 5) = 20.526,p= .006, and self-directed behaviors,F(1, 5) = 13.507,p= .014, and lower inactivity levels,F(1, 5) = 9.239,p= .029. Gorillas were more frequently inactive,F(1, 8) = 22.259,p= .002, and produced lower levels of object manipulation,F(1, 8) = 8.243,p= .021, and feeding,F(1, 8) = 5.407,p= .049. Results are consistent with an association between choice and the expression of species-typical and arousal behaviors in chimpanzees. The effects are less evident in gorillas, but this outcome may be buffered by the species' lower motivation to utilize the outdoor spaces. Findings highlight species-specific reactions to access to choice that may offer insight for enclosure design, management, and nonhuman animal welfare. [ABSTRACT FROM AUTHOR]

Abstract: In captive animal facilities, human staff members are a relevant part of the animals’ social environment in addition to providing care and managing the social group. Structured, predictable interactions and relaxed, spontaneous contacts may all affect the animals’ behavior and well-being, both immediately and in the long term. This study examined the association between unstructured, affiliative caretaker–animal interactions and the behavior of zoo-housed chimpanzees (Pan troglodytes) and Western lowland gorillas (Gorilla gorilla gorilla). The interactions in question included play, spontaneous feeding, and other positive vocal and visual interactions performed through a protective mesh barrier. Behavioral data collected over 48 months were used to identify correlates of caretaker interactions among key behaviors relevant to welfare assessment, including agonism, sexual behavior, abnormal behavior, prosocial behavior, and self-directed behavior, as well as the presence of wounds. In observational sessions containing one or more caretaker interactions, chimpanzees and gorillas both showed higher agonism (P =0.044 and P =0.042, respectively) and lower self-directed behavior (P =0.035 for chimpanzees and P =0.001 for gorillas) than in control samples. Agonism rose in chimpanzees from an average of 0.01–0.12% of overall behaviors, and in gorillas from 0% to 0.1%, while self-directed behavior decreased in chimpanzees from an average of 9.54–7.81% and in gorillas from 11.02% to 7.38%. Chimpanzees also showed lower intraspecific prosocial behavior in samples with caretaker interactions (P =0.044), decreasing from an average of 11.5% to 5.52% of overall behaviors. Finally, gorillas exhibited less abnormal behavior in caretaker interaction samples than in control samples (P =0.029), decreasing from a mean of 2.42–1.77% of overall behaviors. In chimpanzees, higher agonism and lower prosocial behavior are indicative of greater arousal, although we would expect self-directed behavior to rise rather than decrease in that situation. The results in gorillas are mixed with respect to welfare outcomes: higher agonism is indicative of arousal, but lower abnormal and self-directed behaviors suggest a decrease in stress and anxiety. These findings underscore the importance of understanding the influence of all forms of interaction with heterospecifics and demonstrate a need for welfare assessments that include even positively intended interactions. [Copyright &y& Elsevier]

Simple Summary: As animals cannot tell us how they feel, we must develop tests to make inferences about how they are feeling to assess their welfare. Here, we adapted a task that has been previously used with humans and chimpanzees to assess how chimpanzees, gorillas, and Japanese macaques respond to pictures of different emotional valences. Specifically, if the primates perceive emotionally arousing photographs differently as compared to neutral photographs, we would expect them to "trip up" more when responding to emotional stimuli. We presented the primates with a touchscreen task in which they had to select one of two differently colored squares. However, the squares always contained either positive photographs (a preferred food), negative photographs (a snake), or neutral photographs (human-made objects). The primates made more errors in selecting the correct square when the squares contained positive or negative photographs as compared to neutral photographs, indicating that they perceived these differentially, and that this caused them to make mistakes. Thus, the primates' cognitive ability was disrupted by emotional stimuli. This offers important insights into how primates perceive the world around them, and how they process elements that may have negative or positive associations. The Stroop effect describes interference in cognitive processing due to competing cognitive demands. Presenting emotionally laden stimuli creates similar Stroop-like effects that result from participants' attention being drawn to distractor stimuli. Here, we adapted the methods of a pictorial Stroop study for use with chimpanzees (N = 6), gorillas (N = 7), and Japanese macaques (N = 6). We tested all subjects via touchscreens following the same protocol. Ten of the 19 subjects passed pre-test training. Subjects who reached criterion were then tested on a standard color-interference Stroop test, which revealed differential accuracy in the primates' responses across conditions. Next, to test for an emotional Stroop effect, we presented subjects with photographs that were either positively valenced (a preferred food) or negatively valenced (snakes). In the emotional Stroop task, as predicted, the primates were less accurate in trials which presented emotionally laden stimuli as compared to control trials, but there were differences in the apes' and monkeys' response patterns. Furthermore, for both Stroop tests, while we found that subjects' accuracy rates were reduced by test stimuli, in contrast to previous research, we found no difference across trial types in the subjects' response latencies across conditions. [ABSTRACT FROM AUTHOR]

Highlights • We compared Japanese macaque behavior when touchscreens were present and absent. • Affiliation, anxiety-related behaviours and activity were similar between conditions. • Aggression was low overall, but higher when the touchscreens were present. • Aggression was primarily directed from adults to juveniles. • Results should inform implementation of cognitive testing programs. Abstract Cognitive testing programs are being implemented more frequently in zoo settings due to the benefits these programs can provide for the animals, researchers and zoo visitors. However, the impact that cognitive studies have on the welfare of captive animals, particularly for primates in a social group, is debated. Although cognitive testing can be mentally enriching, the provision of monopolisable apparatuses to a primate social group can elicit competition and potentially contribute to negative welfare. We sought to investigate how behaviours changed when a group of 12 Japanese macaques had access to two touchscreen devices. We assessed rates of affiliative behaviours, anxiety-related behaviours, general activity, and aggression over 15 months at matched time periods on days when cognitive testing was available and when it was not. Rates of affiliative behaviours, anxiety-related behaviours, and general activity were not significantly different between conditions. Rates of contact and non-contact aggression were significantly higher during cognitive testing compared to times without cognitive testing (p < 0.05 for both). To further explore this result, we used social network analysis to visualize the aggressive interactions between individual macaques. We found that juveniles were receiving the most aggression. However, because the overall rates of aggression were low and did not deter the macaques from participating in cognitive research, we do not think these results should broadly discourage the implementation of cognitive testing programs. Instead, we intend this study to inform how cognitive testing programs are executed. We also discuss how social interactions and the corresponding welfare implications may differ in closely related macaque species based on species-typical sociality. [ABSTRACT FROM AUTHOR]

Several factors are known to affect the overall well-being of captive apes, including facility design and the presence of and interaction with both familiar and unfamiliar humans. Several studies have examined the effects crowds of varying sizes have on the behavior of a wide taxonomic range of zoo-housed animals, including apes. However, previous investigations of visitor effects on ape behavior vary in scope and methodology, leading to inconsistent results across groups and institutions. Using data gathered through two long-term observation protocols, we aimed to determine how 6 chimpanzees ( Pan troglodytes ) and 5 Western lowland gorillas ( Gorilla gorilla ) housed at Lincoln Park Zoo responded to visitor crowds of various sizes. The dataset, gathered over 12 consecutive months, included both behavioral data collected via focal animal follows, and exhibit use data collected via whole group scans. As with previous studies, we investigated if and how the behavior of the apes varied as the number of visitors near their exhibits increased across several levels of visitor density. In addition, we looked at whether the apes in this study use the indoor areas of their exhibits that are nearest the public (within one meter) at a rate proportional to the size of that area, and whether their use of this space changed as crowd size varied. As crowd size increased, neither chimpanzees (P = 0.97) nor gorillas (P = 0.18) were observed to alter their use of the areas of their exhibit closest to zoo visitors. In addition, both chimpanzees and gorillas were observed in this area at a rate equal to or greater than expected by random movements at all three levels of crowd size analyzed. Crowd size had no effect on the frequency of most behaviors analyzed including abnormal, agonism, and grooming (P > 0.05). We observed a slight effect of crowd size on self-directed behaviors in both species though it was not the case that the largest crowds caused the highest rates of self-directed behavior. Although these data were collected at a single institution, our findings support the argument that well-designed zoo exhibits can be effective in removing the potentially negative effects of large crowds. [ABSTRACT FROM AUTHOR]

For captive chimpanzees, ‘abnormal’ behaviours include behaviours observed only in captivity (i.e. species-atypical behaviours) and those that are performed at higher rates in captivity compared to in the wild. Both types are used as metrics for evaluating captive primates’ welfare. However, categorizing all abnormal behaviours together ignores variation in their etiologies, which limits our ability to understand them and provide useful interventions. Coprophagy (deliberately eating faeces) is an intriguing abnormal behaviour because, unlike many abnormal behaviours, it is performed at higher rates among captive chimpanzees that were mother reared, compared to those that were human reared, and it has been proposed that it represents a socially learnt ‘cultural’ behaviour. Furthermore, coprophagy is observed among both wild and captive animals, although at higher rates in captivity. Typically, coprophagy is classed with other abnormal behaviours by those evaluating captive chimpanzee welfare, but such categorization has arisen from a top–down approach based on a priori assumptions. To apply a bottom–up approach, which would allow us to identify relations between behaviours in chimpanzees’ repertoire, in this study we ran a principal components analysis on the behaviours performed by 60 captive chimpanzees, to determine whether coprophagy should be classified with other abnormal behaviours. The principal components analysis revealed seven factors that we termed social, aggressive, playful, active, feed, abnormal and self-directed. Furthermore, the analysis revealed that coprophagy loaded onto the ‘social’ factor, which included positive social behaviours, and not onto the ‘abnormal’ factor, which included other abnormal behaviours. Supporting previous research, we also found that those chimpanzees that were mother-reared showed higher rates of coprophagy than those that were human reared; there was a significant positive correlation between time spent with conspecifics during the first four years of life and the rate of coprophagy performed by the subjects as adults ( r = 0.575, N = 60, P < 0.001). We discuss these results giving consideration to the practical applications for monitoring and evaluating captive chimpanzee welfare and also from a theoretical perspective about the social learning mechanisms that may underpin the transmission of coprophagy among captive chimpanzees. [ABSTRACT FROM AUTHOR]

• Incidences of wounding were evaluated over a 24 month period in 131 gorillas living in mixed-sex groups. • Sex differences were observed with females receiving significantly more wounds than males. • Wounds were not received uniformly across the body. Wounds to the trunk of adults and face of immatures occurred most frequently. • Presence of a neighboring group did not affect wounding further suggesting that this management approach does not negatively affect welfare. • These data are informative to guiding husbandry practices and population management of gorillas living in zoos. Long-term, multi-institutional assessments have become a reliable tool for evaluating patterns of wounding in zoo-living primates, with results informing on best practices for species-specific care protocols and population management strategies. For western lowland gorillas (Gorilla gorilla gorilla) there has been no detailed reports focused on mixed-sex groups, the most common social group type for this species in zoos. In this study, wounding data were collected over 26 months for 131 gorillas living in 26 social groups at 18 zoos and analyzed in relation to age, sex, and group demographic variables. Adult females received wounds at significantly higher rates than adult males suggesting sexual dimorphism and the disparate social roles of male and female gorillas may differentially affect wounding rates. Group size was associated with increased wounding in adult gorillas, however, wounding rates overall were low in frequency and severity. Wound locations were not randomly located, with wounds to the trunk accounting for 24 % of all wounds. These data provide useful insights that may help inform and improve management of gorillas in mixed-sex groups. Specifically, understanding that vulnerability to wounding may be more prevalent in females compared to males can inform strategies aimed at improving husbandry, health, and welfare and have a positive impact on population management practices for the species. [ABSTRACT FROM AUTHOR]