Primates最新文献

We report behavioral responses to four dying and dead adult companions (two aged alpha males, one high-ranking adult male, and one aged, high-ranking female) in a free-ranging, provisioned group of Japanese macaques, with particular interest in whether external, visible bodily damage to the deceased individuals and social affinity with them influenced responses of group members. All but one moved away or stayed away from the dying or dead individuals when they noticed maggots on them, likely indicating an aversion to maggots (Cases 1, 2, and 3). However, some individuals remained near the corpse of an adult male that had no noticeable external damage, and a juvenile female whose mother was his most frequent proximity partner groomed him (Case 4). One adult female who ate maggots while grooming the dying alpha male (Case 1) and most individuals who remained relatively close to another alpha male's rain-drenched dead body (Case 2) were also affiliated with those two alpha males prior to their deaths. We conclude that Japanese monkeys have a strong tendency to avoid dying and dead adult companions already infested with maggots but that some individuals with social affinity with the deceased may contact or at least remain near the latter for some time. We discuss monkeys' possible perceptions when encountering corpses, in relation to non-human primates' awareness of death.

Understanding the meanings of names given to endangered animals is important because these names might influence how local communities perceive the animals. Influenced by name connotations, these perceptions may shape how communities support or oppose our conservation efforts. Conducted across nine villages within the Batang Toru ecosystem, this research involved 90 respondents. The study incorporated in-depth interviews and content analysis using a qualitative approach. Our findings reveal five local names for the Tapanuli orangutan: 'orang utan,' 'nihagatua,' 'mawas,' 'maos,' and 'juhut bontar.' The term 'juhut bontar,' which translates to bloody meat, is significantly linked to the perception of orangutans as bushmeat, reflecting an attitude not consistent with species conservation. Consequently, we recommend discontinuing this term in local conservation campaigns. Our sample size was insufficient to conclusively determine whether non-indigenous names with potentially positive connotations due to the meaning 'person of the forest' (i.e., 'orang utan' and 'nihagatua') or rather indigenous names with neutral meaning (i.e., 'mawas' and 'maos') support pro-conservation attitudes.

Through primatology, I realized it was possible to examine sociality from a perspective outside of the human species. I joined Kyoto University's Laboratory of Physical Anthropology under the supervision of Imanishi Kinji and Itani Junichiro. I decided to pursue field-based discovery research on Japanese macaques and gorillas aligned with my mentor's frameworks. First, I traversed Japan, investigating macaque ecology, sociality, and morphologic variation. Next, Iinvestigated the socio-ecology of gorillas in Africa. I focused on Grauer's gorillas in Kahuzi-Biega National Park (Zaire), and mountain gorillas in Volcanoes National Park (Rwanda). These populations exhibited differences in the prevalence of multi-male groups, female migration patterns, and male group formations. Under the supervision of Dian Fossey in Rwanda, I studied male and group life histories. Following Fossey's tragic death and The movement of Karisoke Research Centre outside the park. I resolved to collaborate with local researchers and engage in community conservation activities. In Kahuzi, I studied the sympatric coexistence of gorillas and chimpanzees in higher and lower regions. They share habitats and diets but adopt different foraging strategies, particularly during periods of fruit scarcity. Early humans adopted a strategy of "turning weaknesses into strengths."This approach enabled us to colonize diverse environments inaccessible to other primates. Modern society has shifted toward a strategy of "amplifying strengths" through technology, leading to significant degradation of the environment. Field studies of nonhuman primates can shed light on the nature and origins of human societies. Continuation of field research is crucial for envisioning and shaping a prosperous future for humanity.

Understanding activity time budgets is crucial for analyzing primate behavioral variability and adaptation to environmental changes. Given the close interaction between wildlife and humans, conservation and management efforts must consider these phenomena. This study investigated the diurnal activity budget and diet of the olive baboon (Papio anubis) in and around the Chato Natural Forest in Oromia region, Ethiopia. We focused on two troops, namely the Bareda troop (inhabiting marginal areas of the forest where human interference is high) and the Dukko troop (occupying the central area of the forest, with little human disturbance). We used scan sampling to collect data on diurnal activity patterns and dietary regime. Bareda troop spent most of their time feeding, followed by resting, and then moving. Dukko troop also spent most of their time feeding, although less than the Bareda troop, followed by resting and moving. Fruits were the primary food source, comprising 53.4-72.7% of Dukko troop's diet and 33-54.4% of Bareda troops. Leaves constituted the second most significant dietary component, being consumed 8.7-16.3% and 20.9-39.6% of the time by the two troops respectively. Human encroachment alters baboon behavior and activity patterns, increasing competition for resources and heightening conflicts with humans. To promote better human-wildlife coexistence, efforts should focus on minimizing, human interference in natural primate habitats, allowing the animals to thrive and reducing conflict with human.

Camera traps are powerful tools that facilitate ecological monitoring and behavioral observations of non-human primates. Although supposedly non-intrusive, some models generate sound and illumination that elicit behavioral responses from different species. Reactions of primates to camera traps are poorly documented, including those of tarsiers, despite their distinctive auditory and visual specializations. Here, we described the reactions of wild Philippine tarsiers (Carlito syrichta) to camera traps based on existing video records on Leyte Island (N = 12) and characterized the light and sound emissions of the camera traps used for recording. We observed avoidance, attraction, and inspection behaviors from the tarsiers after their looking impulses. Using a spectrometer and ultrasonic acoustic analysis, we found that the camera traps emitted light at predominantly infrared wavelengths with peaks at ca. 850 nm (low glow) and ca. 930 nm (no glow). Some low-glow models produced a faint red glow during recording and a detectable clicking sound upon trigger, whereas the no-glow camera traps emitted infrared light with significant ultraviolet components. Based on spectral sensitivity approximations and audible threshold assessments, we found that the emissions of the camera traps are detectable, not only to tarsiers but also other primate species. Our findings suggest that camera traps influence the behavior of tarsiers. Hence, we advise caution when using camera traps since behavioral reactions may induce bias depending on the framing of studies. We also recommend proper planning when accounting for these behaviors, selecting camera trap models, and designing camera trapping studies.

Social connections within primate groups are continuously changing, and an individual's connectedness within their social network can have important consequences on morbidity and mortality. Here, we examined the effects of early life social experiences and age on social connectedness of captive female olive baboons (Papio anubis). Subjects included 54 mother-reared (MR) and 35 nursery-reared (NR) baboons (4.03 to 19.8 years of age). We conducted four 15-min focal observations and recorded all social interactions. For every possible dyad, we calculated total amount of time in proximity to one another and total amount of time spent grooming (in each direction), then used these data to create interaction matrices. We then calculated a number of direct and indirect measures of social connectedness in UCINET. Direct measures included degree centrality for grooming and proximity. Indirect measures included beta centrality for grooming and eigenvector centrality for proximity. A MANCOVA examining the effects of rearing on the three measures of direct connectedness: (1) in-degree and (2) out-degree centrality for grooming, and (3) degree centrality for proximity revealed an overall significant rearing effect, with age as a significant covariate. Subsequent univariate analyses revealed significant rearing effects on grooming out-degree centrality, in which MR females groomed conspecifics at significantly higher frequencies than NR females. There were no significant rearing effects on grooming in-degree centrality, proximity degree centrality, or any of the indirect social connectedness measures. One possible interpretation of these effects is that NR baboons might not find grooming to be intrinsically rewarding, and therefore have less motivation to groom others. Contrary to our predictions, older females did not have significantly fewer social partners, nor did they spend less time engaging in social interactions, compared to younger females. Overall, the results of this study suggest that among female baboons, early life social experiences affect social connections into adulthood, while age appears to explain less of the observed variation in social connectedness.

In 1986, Japanese macaques of the Arashiyama B group fissioned, with high-ranking females forming the dominant E group and the middle- and low-ranking females forming the subordinate F group (Suzuki et al. in Primates 64:79-90. https://doi.org/10.1007/s10329-022-01024-x , 2023). In 1988, we recorded the dominant-subordinate interactions among adult females in both groups and analyzed them to clarify how they reorganized their dominance relations. The two groups showed contrasting results. Two years after group fission, the past dominance relations among female kin-groups had been largely maintained in E group, whereas the dominance relations among females in F group had been significantly reorganized, with the females from some kin-groups dispersing into various rank positions within the group. In both the E and F groups, the kin-related dyads within the 2nd degree of maternal relatedness (consanguinity) (r ≥ 0.25) tended to follow Kawamura's principles (Kawamura in Primates 1:149-156, 1958), but a considerable number of dyads did not. Such deviations from the principles seemed to derive from multiple factors: past rank reversals between the mothers and daughters, social influences from high-ranking males, and changes in the membership of kin-related females following group fission; for example, disappearances of or separations from mothers. Once rank changes were fixed, however, the relations of the newly emerged mother-daughter and sister dyads again reflected Kawamura's principles.

Compared with wild troops, Japanese macaques (Macaca fuscata), which are commonly housed in cage-like enclosures in zoos and laboratories, face limited feeding opportunities, leading to intense competition and frequent aggression. Such aggression often results in injuries, highlighting the need for methods to reduce aggression in captive settings to improve welfare. This study evaluated the effects of three enrichment strategies-fire hoses with branches, external feeders, and plastic tubs with straw-designed to promote spatial usage and diversify feeding opportunities in a Japanese macaque group in Hirosaki City Yayoi Ikoi Park. The frequency of aggressive behavior and spatial utilization across vertical cage layers was recorded. Generalized linear models revealed that all the tested enrichments significantly reduced intense aggressive and displacement behaviors. Fire hoses increased the usage of the second layer, whereas external feeders and plastic tubs decreased the usage of the top layer, which was used most in the control condition, promoting group dispersion. These interventions improved the environmental opportunity and choice (environmental domain of the Five Domain model), decreased aggression-related injuries (physical health domain), encouraged to express natural behaviors such as climbing and foraging (behavioral domain), and reduced fear and discomfort due to the proximity of dominant individuals (mental domain), collectively supporting enhanced welfare.

Global climate change is directly influenced by human actions due to land use and occupation. In this way, factors related to environments conditions, concomitant with anthropogenic impacts, determine the suitability of environments for species. We analyze the present-day and future suitability of environments for Saguinus martinsi, a primate species endemic to the Brazilian Amazon region. We analyzed two different greenhouse gas emission scenarios, known as Shared Socioeconomic Pathways (SSPs), one "optimistic" (SSP2-4.5) and the other "pessimistic" (SSP5-8.5), described by the Coupled Model Intercomparison Project. We created the models using climatic, edaphic, and topographic variables based on the Euclidean Distance algorithm. Our results indicate that S. martinsi may face severe threats in the near future as a consequence of climate change, given that no environmentally suitable areas were identified for the species in either of the future climate scenarios analyzed. We understand that it is necessary to expand searches for the presence and/or absence of the species in potentially environmentally suitable areas, in addition to consolidating measures to mitigate environmental impacts for the conditions found.

Social play requires communicative abilities that start developing since the first phases of life. Due to their paedomorphic nature, bonobos (Pan paniscus) tend to maintain a playful attitude also in adulthood. Here, we present the case of an adult bonobo (Congo) that has never had any contact with conspecifics in the first 40 years of life. In 2023, Congo underwent an introduction protocol at the Wilhelma Zoo. Prior to the data collection period, he had spent 8 months within the group. The aim was evaluating Congo's playful social competence and his ability to react in a resilient way to others' stimuli. The play sessions involving Congo and two juveniles (CPSs) were compared with play sessions occurring in other adult-juvenile pairs (OPSs). Compared to OPSs, CPSs were shorter and more punctuated by grooming pauses that were totally absent during OPSs. Despite increased grooming, CPSs had a higher risk of escalation into overt aggression from Congo frequently screaming during the interaction. Unlike other adults, Congo never rapidly replicated the partners' playful facial displays, a phenomenon known as rapid facial mimicry. Despite Congo appearing to struggle to manage social play, he responded to other's invitations, thus indicating a presence of play motivation. Albeit being just a case report, our findings emphasize the importance of adult play as a mechanism for social integration, even in individuals entirely unfamiliar with its nuances. Although animals engage in play early in life, it is never too late to play the game and strengthen social bonds.