Recently, many studies have been conducted on manual laterality in chimpanzees. Nevertheless, whether nonhuman primates exhibit population-level handedness remains a topic of considerable debate. One of the behaviors studied has been bimanual coordinated actions. Although recent studies have highlighted that captive chimpanzees show handedness at population level for these tasks, some authors have questioned the validity and consistency of these results. The first reason has been the humanization of the samples. The second one has been that the results refer to animals in American biomedical centers and the studies were conducted by the same team [WD Hopkins et al.]. This article aims to assess the laterality in bimanual coordination (tube task) activities in animals housed in an intermediate environment (Chimfunshi, Zambia). This has been conducted by replicating previous studies on similar samples (Mona Foundation, Spain), and then by extending the results to chimpanzees housed in intermediate settings. Individuals were evaluated through four experimental sessions (tests). Results indicated that 86% of the Chimfunshi sample was lateralized (48% RH, 38% LH). Furthermore, the sample showed population-level right-handedness in the mean handedness index, in Test 1, Test 2, and the first half of the study (Test 112). Rearing experience did not have an influence on handpreference. Taken together, the two sample (intermediate settings: Chimfunshi and Mona) results indicate a clear right-handedness. In conclusion, this replication and extension shows that (1) the Mona and Chimfunshi chimpanzees are right-handed in certain conditions, (2) the results are consistent with those obtained by Hopkins in captive settings, (3) the humanization of the samples does not affect manual laterality, (4) females are right-handed at population-level, but not males, and (5) these results reinforce the fact that the complexity of the task plays a dominant role in the expression of hand laterality among chimpanzees.

Abstracts Primates are at times used as performers in circuses, advertisements, films, and as pets. Most of these animals are socially isolated from their peers. They exhibit behavioral problems and lack important skills for living in a group environment. One of the main challenges primate rescue centers face is creating groups to socialize rescued individuals and promote the development of species-typical behaviors. We monitored a group of 15 chimpanzees (Pan troglodytes) housed at Fundació Mona, a primate rescue and rehabilitation centre, for 8 yr. The aim of the study was to study the rehabilitation process and to establish variables that may influence the behavioral recovery of the chimpanzees. We used scan sampling to assess behavior and two welfare indices over the study period. Our results show that both desirable behaviors and welfare indices increased over time, while nondesirable behaviors decreased. We found no differences between pet and performer chimpanzees, but captive-born subjects recovered better than wild-born. We also established that chimpanzees that were younger at the onset of rehabilitation reached higher levels of social and behavioral competence than those that were older. We conclude that both social group housing and opportunities for the development of species-typical behaviors have a positive effect on the welfare and rehabilitation of performer and pet chimpanzees, but that their previous history influences rehabilitation. Int J Primatol

No abstract

During recent years, handedness of nonhuman primates has been the subject of several studies, especially focused on our closest relatives: the chimpanzees. These studies have dealt with both wild and captive chimpanzees, and they seem to point to divergent conclusions, which have been interpreted as a by-product of the human influence in the captive samples. Here we present the results of a study of 10 chimpanzees (Pan troglodytes). In the past, they were trained in circus and marketing tasks (humanised behaviours), until they were confiscated and accepted into the Mona Foundation (in northeast Spain) in 2000, where they live in a semi-naturalistic environment. This study has been performed through observational bouts without systematic human influence, recording the actions carried out by chimpanzees when performing spontaneous activities. Our results indicate that chimpanzees that were under strong human influence in the past show the same trend in handedness as those living in freedom: few significant lateralities were observed among either individuals or tasks. So, laterality may not be influenced by humanisation. However, this conclusion must be taken as preliminary because very few individuals were studied.

Simple Summary:Hunting is well documented in wild chimpanzees, but has rarely been documented in captive chimpanzees. At Fundació Mona Primate Rescue we have obtained evidence of five episodes of hunting in rehabilitated chimpanzees who had no previous experience of these types of behaviors. This demonstrated that they were able to perform this species-typical behavior in a naturalistic environment without learning it in the wild.Abstract:Predatory behavior in wild chimpanzees and other primates has been well documented over the last 30 years. However, as it is an opportunistic behavior, conditions which may promote such behavior are left up to chance. Until now, predatory behavior among captive chimpanzees has been poorly documented. In this paper, we present five instances providing evidence of predatory behavior: four performed by isolated individuals and one carried out in cooperation. The evidence of group predation involved the chimpanzees adopting different roles as pursuers and ambushers. Prey was partially eaten in some cases, but not in the social episode. This study confirms that naturalistic environments allow chimpanzees to enhance species-typical behavioral patterns.