The Social Rank of Zoo-Housed Japanese Macaques is a Predictor of Visitor-Directed Aggression

Factors affecting captive female giraffe stress response: Male presence, small enclosure, and low temperature

To improve animal welfare based on suitable social housing conditions, it is important to understand the factors that trigger high-stress responses. Wild giraffes live in a fission-fusion society and males and females are rarely in the same herd for a long period. The captive condition of belonging to a herd with the same individuals for months or years is uncommon in nature. To understand the effect of male presence on female stress levels, fecal glucocorticoid metabolite (fGCM) levels and social interactions in two captive female giraffes were investigated. Additionally, the effect of enclosure size and temperature on fGCM level and social interactions were examined. The results showed no significant difference in the fGCM levels of females based on male presence. The frequency of agonistic behavior by the dominant female toward the subordinate female was significantly increased when a male was present. The subordinate female was significantly less likely to approach the dominant female and showed decreased affiliative and agonistic interactions toward the dominant female when a male was present. The frequencies of agonistic interactions between females were higher in the small enclosure regardless of male presence. Low temperature triggered higher fGCM levels and increased agonistic interaction in an aged female. The findings of this study suggest that these multiple factors should be considered individually to promote the welfare of captive giraffes.

Invited review: Social dominance in dairy cattle: A critical review with guidelines for future research

Cattle are gregarious animals able to form social relationships. Dominance is one of the most widely studied social behaviors of dairy cattle, especially cows confined indoors. However, much of the past dairy cattle research has used an unstandardized approach, differing in definitions and conceptual understanding of dominance, as well as their methods of data collection and dominance calculation. The first of the 3 aims of this review is to evaluate how dominance relates to the social behavior of housed dairy cows. Cows engage in agonistic interactions to establish and reinforce dominance relationships. An individual's dominance is influenced by intrinsic characteristics, such as personality, and extrinsic factors, including group composition. When competing for resources, agonistic interactions can also be influenced by individual motivational differences, such as hunger, which may diminish the role of dominance in regulating competition. Our second aim is to critically review methods used to assess dominance in cows. This includes discussions on the effect of time and location of data collection on measured values as well as the viability and limitations of some dominance calculation methods. We propose that different methodologies lend themselves to different types of research questions. For example, the use of data stream-based methods that consider the sequence of interactions are useful for estimating how dominance fluctuates with changing conditions and can be used in a dynamically changing group. In contrast, matrix-based methods that aggregate social interactions may be best for identifying the social position of individuals and understanding how social characteristics influence the attributes of a stable hierarchy. Our third aim is to discuss the future of dominance research. We use a flowchart to illustrate guidelines for a more standardized approach to measuring dominance in cattle. We also identify areas in need of further conceptual clarification, suggest practical applications of dominance when managing dairy cattle, and discuss some limitations of dominance research.

Do zoo-housed primates retreat from crowds? A simple study of five primate species

An animal's welfare state is directly influenced by the mental state, which is shaped by experiences within the environment throughout the animal's life. For zoo-housed animals, visitors to the zoo are a large part of that environment and a fluctuating influence within it. This study examines the impact of zoo visitors on the space use of five species of zoo-housed primates (Eastern black-and-white colobus monkeys, Colobus guereza, n = 5, Allen's swamp monkeys, Allenopithecus nigroviridis, n = 2, DeBrazza's monkeys, Cercopithecus neglectus, n = 3, Bolivian gray titi monkeys, Callicebus donacophilus, n = 3, and crowned lemurs, Eulemur coronatus, n = 3). Specifically, we considered whether primates' distance from visitor areas changed as crowd sizes increased. Data were collected using the ZooMonitor app. Observers recorded spatial coordinates for each animal over periods ranging from 12 to 32 months. Data were analyzed using two types of regression models (linear and logistic) to examine the influence of visitors on the location of the primates. Both analyses revealed a statistically significant but small decrease in primate distance from visitor viewing glass as the number of visitors increased. Behavioral indicators of welfare were also unaffected by the presence of visitors. These results suggest that, with additional validation, distance from visitors may be one promising, simple way to evaluate the influence of visitors on primate welfare.

The relationship between personality, season, and wounding receipt in zoo-housed Japanese macaques (Macaca fuscata): A multi-institutional study

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.

Gaps in Live Inter-Observer Reliability Testing of Animal Behavior: A Retrospective Analysis and Path Forward

Observational behavior research is an important activity for zoos and aquariums, often being conducted to provide insights into welfare and guide management decisions. This research relies on standardized protocols to ensure consistent data collection. Inter-observer reliability, where untrained observers are tested against the behavior identifications of an expert observer, represent a critical internal validation process. Recent software advances have made reliability testing easier and more accessible, but there is limited guidance on what constitutes a strong reliability test. In this study, we reviewed historic reliability test data from Lincoln Park Zoo’s on-going behavior monitoring program. Six representative species were chosen that included 645 live pairwise reliability tests conducted across 163 total project observers. We identified that observers were being tested on only approximately 25% of the behaviors listed and defined in the species ethograms. Observers did encounter a greater percent of the ethogram with successive reliability tests, but this gap remained large. While inactive behaviors were well-represented during reliability tests, social and other non-maintenance solitary behaviors (e.g., exploratory, scent marking, play, etc.) did not frequently occur during tests. While the ultimate implications of these gaps in testing are unclear, these results highlight the risks of live reliability testing as an inherently non-standardized process. We suggest several approaches to help address these limitations, including refining ethograms, reconsidering criteria, and supplementing live training with video. We hope this self-critique encourages others to critically examine their methods, enhance the quality of their behavioral data, and ultimately, strengthen conclusions drawn about animal behavior and welfare.

Widespread Behavioral Responses by Mammals and Fish to Zoo Visitors Highlight Differences between Individual Animals

The impact that humans have on zoo animals can vary based on the species of animal, exhibit design, and individual differences in behavioral responses. We independently analyzed data from 10 never-published studies that examined the impact of zoo visitors on zoo animal behavior. Of the 16 species studied, 90.9% of the mammal species and 60.0% of the fish species demonstrated a change in at least one behavior based on zoo visitor abundance or visitor behavior (e.g., noise, solicitation of interactions from zoo animals). In addition, behavioral changes associated with zoo visitors were present in animals housed in exhibits where there was direct contact with zoo visitors, as well as in exhibits where there was indirect contact and no direct contact. Individuals often varied in their behavioral responses, and some individuals appeared to seek out interactions with visitors. Our findings demonstrate that short-term research projects can provide valuable insight into individual animal-level and species-level responses to visitor abundance and visitor behavior in the zoo setting. We recommend that behavioral assessments focus on the analysis of behaviors of individual animals whenever possible, and we recommend that exhibits provide areas that allow for animals to retreat from the public view.

Do zoo visitors induce attentional bias effects in primates completing cognitive tasks?

While previous research has focused on the impact of visitors on zoo-housed animals' behavior, here, we evaluated the impact of visitors on the performance of four zoo-housed Japanese macaques (Macaca fuscata) in a cognitive task. The macaques completed a touchscreen-based match-to-sample task in glass-sided booths at the perimeter of their enclosure, adjacent to a visitor viewing area. The task was novel to all macaques at the start of this study but over the 6-month testing period the macaques showed increased accuracy on the task, suggestive of learning. We recorded the number of visitors within the viewing area roughly every 12 trials each macaque completed. We categorized visitor counts as small (0-20), medium (21-40), and large (41-60) crowds and we considered the macaques' response latencies and accuracy by crowd size and study period (first 3 months versus second 3 months). If visitor presence negatively influenced performance, we predicted that macaques' accuracy would decrease but response times would increase with crowd size. We found effects of crowd size and study period on the macaques' accuracy. In the first period, the macaques performed at chance and accuracy did not differ across crowd categories. In the second period, the macaques' accuracy improved as compared to the first period, but their accuracy was mediated by crowd size: the macaques were significantly more accurate in the presence of small crowds than medium or large crowds. The macaques' response latencies also varied by study period and crowd size, but we found no evidence of a response-slowing effect.

Documenting Aggression, Dominance and the Impacts of Visitor Interaction on Galápagos Tortoises (Chelonoidis nigra) in a Zoo Setting

Ensuring high levels of welfare is imperative for modern zoos, but such organisations must also engage visitors in order to successfully spread awareness and raise conservation funds. It is therefore important to understand the responses of animals to visitor interaction to optimise welfare. Often, the opportunity to interact with humans may be enriching for animals, but in other contexts, this interaction may have negative welfare effects. We observed captive female Galápagos giant tortoises (Chelonoidis nigra) to describe aggressive interactions, characterize hierarchy using Elo ratings and assess the impact of visitor interactions. Elo ratings indicated that one individual was dominant over two equally ranked subordinates; aggressive interactions are discussed in this context. We detected significant effects of the presence of visitors and visitor type (keepers, vets or public) within the enclosure on aggression and activity. We suggest that previous miscategorisation of a natural behaviour (the finch response) as an operantly conditioned behaviour, rather than a fixed action pattern, may have triggered aggression. We then document changes made to the management of the animals to mitigate the impacts discovered. This work highlights the importance of empirical evidence in determining optimal management strategies for zoo animals with regards to public interactions and animal welfare.