American Journal of Primatology最新文献

The authorship of Brachyteles arachnoides has traditionally been ascribed to É. Geoffroy Saint-Hilaire, 1806. However, É. Geoffroy Saint-Hilaire's original description was based entirely on secondary accounts, namely, Browne's (1756) Simia 2 and Edwards' (1764) report of a brown, long-limbed, and four-fingered monkey, without directly examining specimens or illustrations. Browne's Simia 2 describes a large brown primate with a prehensile tail and four-fingered hands in Jamaica, characteristics that could apply to either Ateles or certain Brachyteles populations. Edwards' account, meanwhile, references two four-fingered “spider monkeys” observed in London but lacks sufficient detail for definitive taxonomic assignment. Historical trade data further undermine this link, as 18th-century Jamaica likely hosted Colombian/Panamanian primates, with no evidence of Brazilian primate imports. Étienne Geoffroy Saint-Hilaire obtained the first verifiable Brachyteles specimen only in 1808, seized during Napoleon's Lisbon campaign. His 1809 redescription, including an illustration and the specimen MNHN-ZM-2007-1475, meets modern taxonomic standards, whereas the 1806 name, based solely on ambiguous accounts, fails ICZN criteria for type association. We argue that Ateles arachnoides É. Geoffroy Saint-Hilaire, 1806, constitutes a nomen dubium, as it cannot be tied to verifiable material. Instead, we validate Ateles arachnoides É. Geoffroy Saint-Hilaire, 1809, with MNHN-ZM-2007-1475 as the holotype by monotypy. This redefinition stabilizes the species' nomenclature, anchoring it to a concrete specimen and Geoffroy Saint-Hilaire's empirically grounded 1809 work. By resolving these historical ambiguities, we provide a clearer framework for understanding Brachyteles taxonomy and highlight the importance of type specimens in early primatological classifications.

Social media platforms today are teeming with images of wildlife as pets, and studies have emerged investigating the role social media plays on the public's perception of primates and their desirability as pets. This study explores the presentation of nonhuman primates and video engagement, defined as user interactions through likes, comments, shares, and views, on the social media platform TikTok. We examined 1378 videos from 173 different TikTok content creators sharing primate videos. Most content depicted primates within a household (43.1%), indicating they are often shown in the context of being pets. This is cause for concern because the portrayal of primates in anthropogenic settings or in contact with humans makes them more desirable as pets to viewers. We also found significant differences in engagement rate based on the location of the video and the species of primate present. Households, zoos, sanctuaries, and wild settings received higher levels of user engagement than other captive or exploitative settings. Smaller primates, mostly platyrrhines, were also found to be more engaging than other species. When variables were clustered using a Multiple Correspondence Analysis, we compared the newly created dimensions against engagement rates using a correlation matrix. We found weak, but significant correlations, with themes representing higher human or anthropomorphic influence receiving better engagement. Because social media can be a source of powerful influence on viewers, rampant presentation of primates as pets or in anthropogenic settings is concerning from a conservation and welfare perspective. However, content from zoos, sanctuaries, and field researchers with imagery representing primates in accredited captivity or in their natural habitats could potentially discourage audiences from regarding primates as making appropriate pets. In turn, this could establish a pathway for TikTok to pivot from being a threat to becoming a tool in primate conservation.

In social animals, aggression is a group matter not involving only the opponents. Witnessing a conflict can induce tension and distress in bystanders (i.e., individuals not involved in either the conflict or post-conflict affiliation with the aggressor and aggressee). For this reason, bystanders can engage in post-conflict affiliative exchanges to reduce tension and distress, a phenomenon known as Quadratic Post-Conflict Affiliation (QPCA). This study investigated the occurrence of QPCA in a group of chimpanzees (Pan troglodytes, N = 15) housed at ZooParc de Beauval, France. Our findings confirmed the presence of QPCA in chimpanzees under study (group QPCA tendency: 5.60% ± 2.55 SE). QPCA was primarily directed towards males, who usually tended to be more influenced by the ongoing aggression and could potentially redirect further aggression towards bystanders. High-ranking bystanders were contacted more frequently than low-ranking ones, as the former can potentially provide immediate protection against other aggressors and offer greater tolerance. Additionally, bystanders were less frequently targeted by aggression when QPCA was present than when it was absent. Thus, QPCA may function as a protective mechanism against aggression by other group members by reducing the chance that bystanders become victims for redirected aggression (Bystander Protection Hypothesis). However, QPCA failed in reducing the levels of bystanders' anxiety-related behaviors. In conclusion, QPCA may be one of the behavioral strategies used by chimpanzees to navigate social challenges, maintain group cohesion, and mitigate aggression.

Primate foraging behaviors are influenced by a variety of factors including the physical and mechanical properties of food items. Golden monkeys (Cercopithecus mitis kandti) inhabiting Volcanoes National Park (VNP), Rwanda, rely heavily on mechanically challenging bamboo shoots and bamboo leaves for the bulk of their diet. We examined the oral processing behaviors of golden monkeys and predicted that bamboo shoots would be characterized by more incising and post-canine crushing behaviors needed to remove tough outer casings and process culms while leaves would require more mastications compared to other food items. We also predicted that juveniles would utilize more incisions and post-canine crushing behaviors to process bamboo shoots and more mastications to process leaves due to the reduced foraging efficiency characteristic of juveniles. We opportunistically filmed habituated groups of golden monkeys foraging during November–December 2022 and January–March 2024 (n = 328 videos). Oral processing behaviors (including incision, canine puncture, post-canine crushing, and mastication scaled to ingestive action) were scored from video footage using Behavioral Observation Research Interactive Software (BORIS). We found that bamboo shoots required more post-canine crushing behaviors compared to other food categories and that non-bamboo leaves required more mastications than bamboo leaves and shoots, respectively. Juveniles did not use more oral processing behaviors per ingestive action, although the inability to control for the size or amount of food ingested may obfuscate these results. Our findings show that golden monkeys adjust their oral processing behaviors to different food items and the routine use of post-canine crushing behaviors may help explain the pronounced tooth wear characteristic of golden monkeys in VNP.

The immature period is an essential time of physical and behavioral development in which individuals prepare to navigate their environment as adults. Activity budgets provide valuable insight into the tradeoffs individuals make based on their energetic priorities. We hypothesized that energetic priorities differ across the stages of development based on the distinct social and ecological needs of that stage. We analyzed 31,113.5 h of focal instantaneous sampling data from 2007 to 2024 on 73 Verreaux's sifaka (Propithecus verreauxi) living in Kirindy Mitea National Park, Madagascar to investigate the effects of age class, sex, and seasonality on activity budgets. Juveniles and subadults devoted significantly more time to social activity than adults. Subadults fed less than other age classes, and we detected no differences in resting among age classes. Among all age classes, males devoted more time to social activity than females, and all age classes displayed sex differences in additional activities. All age-sex classes exhibited similar seasonal patterns in activity budgets. Our results indicate that social activity may be especially important in the developmental period to gain experience and establish social relationships before adulthood. Sex differences in social activity appear to emerge earlier than adulthood as a predisposition for the reproductive roles of adulthood. Overall, we found that energetic priorities differ between stages of development, and evidence is mixed regarding whether these differences are primarily due to the onset of reproduction.

A range of ecological and social factors have been shown to affect early-life behaviour in mammals. Primate infants are altricial and thus unable to move independently at birth. As a result, infants in some species are continuously held or carried (handled) by their mother or another caregiver (allomother). Variation in the amount of time infants move independently can provide insight into the costs and benefits associated with this developmental milestone. In this study, we sought to investigate what environmental conditions are associated with independence in an arboreal primate, the Rwenzori Angolan colobus (Colobus angolensis ruwenzorii). We followed 29 infants from birth until 4 months, collecting data on whether the infant was handled or independent. We report the age-sex make up of infant handlers and show that fruit availability was positively associated with infant independence, and maternal movement frequency was negatively associated with infant independence. We suggest that greater maternal energy balance during early infancy allows mothers to divert more energy to infants, promoting their independent movement. Further research should assess the maternal physiology underlying these trends and whether earlier independent movement has long-term fitness effects.