Activity synchrony and travel direction synchrony in wild female Japanese macaques.

The degree of behavioural synchrony of animals within a group can be considered a reflection of how individuals adjust their behaviours to manage the costs/benefits accompanying group-living. In this study, we focused on activity synchrony and travel direction synchrony as behavioural synchrony. We aimed to quantify the degree of behavioural synchrony and identify which factors can affect the synchrony in wild females of Japanese macaques.

Infant cannibalism in wild white-faced capuchin monkeys.

Cannibalism has been observed in a variety of animal taxa; however, it is relatively uncommon in primates. Thus, we rely heavily on case reports of this behavior to advance our understanding of the contexts under which it occurs. Here, we report the first observation of cannibalism in a group of wild white-faced capuchin monkeys ().

Behavioral responses to changes in group size and composition: a case study on grooming behavior of female Japanese macaques (Macaca fuscata yakui).

Primates flexibly change their grooming behavior depending on group size and composition to maintain social relationships among group members. However, how drastic social changes influence their grooming behavior remains unclear. We observed the grooming behavior of adult female Japanese macaques in two groups temporarily formed as one-female groups from multi-female groups and compared their behaviors between the multi-female and one-female periods.

Activity and social factors affect cohesion among individuals in female Japanese macaques: A simultaneous focal-follow study.

Understanding cohesion among individuals within a group is necessary to reveal the social system of group-living primates. Japanese macaques (Macaca fuscata) are female-philopatric primates that reside in social groups. We investigated whether individual activity and social factors can affect spatio-temporal cohesion in wild female Japanese macaques.

Sleep duration is affected by social relationships among sleeping partners in wild Japanese macaques.

Co-sleeping behaviour, such as sharing a sleeping site or bed, should play an important role in determining sleep structure in mammals by mitigating predation pressure and harsh abiotic conditions during sleep. Although environmental factors surrounding sleeping sites have been studied, there is very little information on the effects of the social environment within the site on sleep in animals other than humans. Here, we quantified the duration of nighttime sleep of wild primates during behavioural observations.

Coprophagy-related interspecific nocturnal interactions between Japanese macaques (Macaca fuscata yakui) and sika deer (Cervus nippon yakushimae).

The influence of sympatric large animals on the sleeping behavior of primates in the wild is still largely unknown. In this study, we observed behaviors of wild Japanese macaques (Macaca fuscata yakui) at their sleeping sites, using a highly sensitive video camera. We found evidence of nocturnal interspecific interactions, such as agonistic interactions, between Japanese macaques and sika deer (Cervus nippon yakushimae).