The purpose of the present study was to push the boundaries of cooperation among captive chimpanzees (Pan troglodytes). There has been doubt about the level of cooperation that chimpanzees are able to spontaneously achieve or understand. Would they, without any pre-training or restrictions in partner choice, be able to develop successful joint action? And would they be able to extend cooperation to more than two partners, as they do in nature? Chimpanzees were given a chance to cooperate with multiple partners of their own choosing. All members of the group (N = 11) had simultaneous access to an apparatus that required two (dyadic condition) or three (triadic condition) individuals to pull in a tray baited with food. Without any training, the chimpanzees spontaneously solved the task a total of 3,565 times in both dyadic and triadic combinations. Their success rate and efficiency increased over time, whereas the amount of pulling in the absence of a partner decreased, demonstrating that they had learned the task contingencies. They preferentially approached the apparatus when kin or nonkin of similar rank were present, showing a preference for socially tolerant partners. The forced partner combinations typical of cooperation experiments cannot reveal these abilities, which demonstrate that in the midst of a complex social environment, chimpanzees spontaneously initiate and maintain a high level of cooperative behavior.

Our species is routinely depicted as unique in its ability to achieve cooperation, whereas our closest relative, the chimpanzee (Pan troglodytes), is often characterized as overly competitive. Human cooperation is assisted by the cost attached to competitive tendencies through enforcement mechanisms, such as punishment and partner choice. To examine if chimpanzees possess the same ability to mitigate competition, we set up a cooperative task in the presence of the entire group of 11 adults, which required two or three individuals to pull jointly to receive rewards. This open-group set-up provided ample opportunity for competition (e.g., freeloading, displacements) and aggression. Despite this unique set-up and initial competitiveness, cooperation prevailed in the end, being at least five times as common as competition. The chimpanzees performed 3,565 cooperative acts while using a variety of enforcement mechanisms to overcome competition and freeloading, as measured by (attempted) thefts of rewards. These mechanisms included direct protest by the target, third-party punishment in which dominant individuals intervened against freeloaders, and partner choice. There was a marked difference between freeloading and displacement; freeloading tended to elicit withdrawal and third-party interventions, whereas displacements were met with a higher rate of direct retaliation. Humans have shown similar responses in controlled experiments, suggesting shared mechanisms across the primates to mitigate competition for the sake of cooperation.

There is considerable research on why cats are initially relinquished to shelters, but much less attention has been given to returns, despite the significant implications for shelter capacity and cat welfare. Furthermore, the structure of many databases fails to account for cats who are returned beyond 30 days, despite this making up a substantial portion of returns. In the current study, we examined common risk factors and reasons for return in a population of 2642 shelter cats. We found that cats who were older at the time of adoption or had a bite history had an increased risk of return, whereas cats that were in foster care prior to adoption had a decreased risk of return. We divided the returns by the time to return (30 days: long term) to examine whether time to return had an impact. Approximately half the cats were returned in the short term. Cats were more likely to be returned for reasons, such as behavior, unwanted, and other pet in the short term and personal reasons, cost, euthanasia, and stray in the long-term return. Strategies to reduce returns should consider different solutions for short and long returns to maximize effectiveness.

The merits of various housing options for domestic cats in shelters have been debated. However, comparisons are difficult to interpret because cats are typically not able to be randomly assigned to different housing conditions. In the current study, we attempted to address some of these issues by creating a retrospective matched cohort of cats in two housing types. Cats in group housing (GH) were matched with cats in single housing (SH) that were the same age, sex, breed, coat color, and size. Altogether we were able to find a match for 110 GH cats. We compared these two groups on several measures related to their experience at the shelter such as moves and the development of behavioral problems. We also compared these groups on outcomes including length of stay, live release, and returns after adoption. We found that while the frequency of moves was similar in both groups, SH cats were more likely to be moved to offsite facilities than GH cats. SH cats also spent a smaller proportion of time on the adoption floor. Length of stay and, live release and returns after adoption did not significantly differ across groups, however GH cats were two times as likely to be returned after adoption. Future research should look at the behavioral impacts of shelter decision-making regarding moving and management of cats in different housing systems.

Colony housing of cats allows shelters to maximize the number of cats housed in limited space. Most research on colony-housed cats examines stress in relation to group size or enclosure size. While this is important for evaluating welfare, it is equally important to understand how cats are interacting socially in these colonies. We observed 259 adult cats housed in groups of two to eight individuals. Scan samples were used to assess how frequently individual cats were in close proximity to other cats. These data were used to measure individual differences in sociability and patterns of proximity to certain partners. We used information about the past history of the cat, which was collected upon admission to the shelter to identify predictors of time spent in proximity. There was a high degree of inter-individual variability in sociability. Strays tended to spend less time in proximity to other cats, and this effect was most pronounced in females.However, none of the information collected upon admission predicted patterns of proximity to certain partners, or which cats spent time in association witheach other. Future studies should explore the implications of differences in sociability by associating observations of social behavior and stress behaviors.