American Journal of Primatology最新文献

{"title":"Urinary Estradiol in Captive Bonobos: Variation With Reproductive State and Sexual Swelling","authors":"Sara Cotton,&nbsp;Klaree Boose,&nbsp;Sedona Espstein,&nbsp;Audra Meinelt,&nbsp;Josh Snodgrass,&nbsp;Frances White","doi":"10.1002/ajp.70041","DOIUrl":"https://doi.org/10.1002/ajp.70041","url":null,"abstract":"<p>Estradiol is known to have a variety of biological and behavioral effects, but monitoring its function is complex given the many factors influencing its variation. This necessitates large sample sizes which are challenging in captive and wild situations. This study validates the use of opportunistically collected urinary estradiol levels (E2) for use in reproductive monitoring and behavioral research in bonobos (<i>Pan paniscus</i>). We analyzed frozen urine samples from four Columbus Zoo adult females over 4 years for estradiol and creatinine concentrations (<i>n</i> = 117). While E2 was significantly higher in pregnant versus nonpregnant females (F = 66.30, <i>df</i> = 1, <i>p</i> &lt; 0.001) it was not significantly different between lactating and regularly cycling females (F = 0.40, <i>df</i> = 1, <i>p</i> = 0.5304). Among the regularly cycling females, there was a significant positive regression between E2 and sexual swelling size (F = 4.43, df = 1, 81, <i>p</i> = 0.0384). No differences in E2 variation were detected between individuals in this study. Specifically, when the amount of variation in estradiol due to sexual swelling was statistically controlled for, there was no significant effect of age (<i>n</i> = 83, r = 0.08059, <i>p</i> = 0.4689) or rank (<i>n</i> = 83, r = 0.1361, <i>p</i> = 0.22) on estradiol variation. Overall, these findings indicate that opportunistically sampled urinary estradiol can be paired with visual observation to help detect changes in reproductive status. The shift from lactational amenorrhea back to estrogen cycling may be less clearly defined than expected, and uneven sampling may exacerbate difficulty in detecting some of the more subtle shifts in estradiol levels. While it is known that extended maximal tumescence in bonobos may function to obscure the exact date of ovulation, we did confirm that ratings of visual tumescence still provide useful information regarding relative estradiol levels. By publishing more methodologies and results of this kind, we hope to promote the continued study of estradiol in bonobos as it is relevant to both health monitoring and behavioral research goals.</p>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajp.70041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the Evolutionary History of cis-Andean Alouatta (Atelidae, Alouattinae) Through Mitochondrial Genomes","authors":"Cíntia Povill,&nbsp;Fabrícia F. Nascimento,&nbsp;Larissa Souza Arantes,&nbsp;Maximilian Driller,&nbsp;James Kieran Sullivan,&nbsp;Fernando Araujo Perini,&nbsp;Filipe Vieira Santos de Abreu,&nbsp;Ricardo Lourenço de Oliveira,&nbsp;Fabiano Rodrigues de Melo,&nbsp;Cecília Bueno,&nbsp;Camila J. Mazzoni,&nbsp;Cibele Rodrigues Bonvicino","doi":"10.1002/ajp.70043","DOIUrl":"https://doi.org/10.1002/ajp.70043","url":null,"abstract":"<p><i>Alouatta</i>, a genus widely distributed throughout South and Central America, displays remarkable species diversity across various morphoclimatic domains. To clarify the ancestral distribution and its role in the radiation of <i>Alouatta</i>, our study employed time-tree phylogenetic analyses to better understand the current distribution patterns of the <i>cis-</i>Andean species. We generated 36 mitogenomes, including a species and representatives of populations not previously analyzed, to reconstruct a molecular-dated tree, estimate genetic distance-based analyses, and infer the ancestral distribution range of <i>Alouatta</i>. Our study suggests an initial split within the <i>Alouatta</i> during the Miocene, leading to the separation of the <i>cis-</i>Andean and <i>trans</i>-Andean clades. Through ancestral range reconstruction, we found that the most recent common ancestor of <i>Alouatta</i> was broadly distributed across South America. Within the <i>cis-</i>Andean clade, two major splits were identified. One split revealed a close relationship between the Amazonia-endemic species <i>A. seniculus</i> and <i>A. caraya</i>, a species adapted to open-dry domains, with ancestral range in the Amazonia and dry-open domains. In contrast, for the <i>A. guariba</i> and <i>A. belzebul</i> groups, which occur in Amazonia and the Atlantic Forest, the ancestral range included both domains. The diversification of the <i>Alouatta</i> was driven by two cladogenesis events. The formation of the extant species was primarily driven by founder events during the Pleistocene and involved long-distance dispersal events with posterior population isolation. These events played a crucial role in the formation of new populations that underwent rapid divergence, resulting in distinct phylogenetic lineages. Our findings shed new light on the origins of <i>cis-</i>Andean lineages of <i>Alouatta</i> across a broad geographic range, as well as the emergence of more recent taxa during the Pleistocene. This provides insights into their relationships, highlighting the crucial role of Pleistocene climatic changes and founder events in shaping the diversification and geographic distribution of extant species.</p>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajp.70043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143909451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is Primate Cone Ratio Variation Functional and Adaptive?","authors":"Rachel A. Munds,&nbsp;Amanda D. Melin,&nbsp;James P. Higham","doi":"10.1002/ajp.70038","DOIUrl":"https://doi.org/10.1002/ajp.70038","url":null,"abstract":"<div>\u0000 \u0000 <p>Variation in animal perception provides excellent opportunities for studying adaptation. Unusually, primates exhibit a great deal of inter- and intra-specific visual system variation. Here, we discuss what is known about the retinal cone mosaic, and the sources of variation in primate cone types and their relative expression. We focus on catarrhines (African and Asian monkeys and apes and humans), which have evolved uniform trichromacy, exhibiting short- (S), medium- (M), and long-wave (L) cones. Catarrhines generally exhibit high inter-specific consistency in the peak sensitivities of their L and M sensitive cones. One under-explored component of variation is the relative expression of those cones, that is, the L:M ratio. Across catarrhines, the mean L:M ratio is 1:1, with some limited intraspecific variation. Intriguingly, humans show two big differences compared to other catarrhines. Firstly, their mean L:M ratio is shifted to 2:1. Secondly, they show vast (75-fold) intraspecific L:M ratio variation. We discuss evidence as to whether this difference in the mean ratio, and this high intraspecific variation, are likely to have functional consequences, concluding that indeed this variation likely impacts color perception. We finish by suggesting possible explanations for the higher mean ratio of L:M cones in humans, highlighting similarities with other aspects of our color vision that differ from other catarrhines. We hope that the suggestions and questions we raise will inspire future research on primate cone ratios.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143888917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highs and Lows of Arboreal Life: Space use and Movement Strategies of Lion-Tailed Macaques (Macaca silenus) in the Western Ghats of India","authors":"Sikha Hariharan,&nbsp;Krithi K. Karanth,&nbsp;Divya Vasudev","doi":"10.1002/ajp.70042","DOIUrl":"https://doi.org/10.1002/ajp.70042","url":null,"abstract":"<div>\u0000 \u0000 <p>Lion-tailed macaques (<i>Macaca silenus</i>), endemic to the Western Ghats of India, are increasingly threatened by habitat loss and degradation, and are vulnerable to environmental change. Insights into their spatial ecology can reveal the strategies that enable these macaques to navigate and use spatially complex heterogeneous spaces. This is crucial for conservation, given the increasing human disturbance in and around the Western Ghats. This study, conducted in Silent Valley National Park between January and June of 2019, 2022, and 2023, focused on two macaque troops occupying habitats with varying human presence—in the park's core (Sairandhri) and in the buffer (Keeripara). The observed group sizes of the Sairandhri and Keeripara troops were 51 and 21, respectively. We examined differences in the spatial ecology of these troops by assessing their vertical space use, two-dimensional (2D) and three-dimensional (3D) home ranges, and using an integrated step-selection function to understand movement-based habitat selection. We observed similarities in movement patterns across the two troops, with notable differences mainly in their vertical use of the forest. The Keeripara troop, resident in a more disturbed area, utilized a smaller home range (1.80 km²). They spent 94.2% of their time in mid-level canopy (6–20 m), descending rarely (1.1%) into lower strata (≤ 5 m), likely due to perceived high risk from predators and humans, and proximity to roads. The Sairandhri troop, resident in the less disturbed area, had a larger home range (3.05 km²) and exhibited greater terrestriality (11.3%), with 84.2% observed time in mid-canopies. Both troops preferred areas with canopy cover and fruiting trees, displaying similar slow movements (indicated through small step lengths and large turning angles) near these resources. Our findings suggest that lion-tailed macaques may be less strictly arboreal than previously believed, displaying more terrestriality in less disturbed habitats. Strategic use of 3D space based on local ecological and anthropogenic conditions highlights the need for conservation efforts that maintain canopy connectivity to support the ecological flexibility of this vulnerable species.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 5","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143879915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is Sociability Generally Linked to Infection? A Study Based on Rhesus and Japanese Macaques","authors":"Zhihong Xu,&nbsp;Chengfeng Wu,&nbsp;Yun Yang,&nbsp;Alba Castellano-Navarro,&nbsp;Emilio Macanás-Martínez,&nbsp;Bojun Liu,&nbsp;Tao Chen,&nbsp;Xiaochen Ma,&nbsp;Andrew J. J. MacIntosh","doi":"10.1002/ajp.70037","DOIUrl":"https://doi.org/10.1002/ajp.70037","url":null,"abstract":"<div>\u0000 \u0000 <p>Parasite infection is one key risk inherent in group living and is considered to influence the formation and evolution of animal societies. Previous studies investigating the relationship between sociability (a measure of an individual's level of social engagement) and parasite infection have yielded mixed results, with some observing positive relationships between social network centrality and infection and others observing negative or no sociability-infection links. Here, we aggregated behavioral and parasitological data from three groups of rhesus macaques (<i>Macaca mulatta brevicaudus</i>) in China and two groups of Japanese macaques (<i>Macaca fuscata</i> and <i>Macaca fuscata yakui</i>) to test whether sociability generally predicts geohelminth infection in macaques with similar social structure. We discovered variability in the relationship between sociability and geohelminth infection across these different groups of macaques, and results did not support a general pattern linking sociability to geohelminth infection. Among the five groups, we found a significant positive relationship between sociability and infection in only one group. These results call into question how generally useful an indicator social network centrality metrics are in predicting geohelminth parasite infection across individuals, at least relative to other factors that influence infection dynamics. We discuss potential confounds when examining relationships between sociability and infection across populations and groups, and encourage future studies that can account for these while focusing on the mechanisms that might link social factors and parasite infection to fully understand this relationship.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electrocutions in Free-Ranging Platyrrhine Nonhuman Primates: Diagnostic Features for a Threatening Condition","authors":"Rafaela M. Barros,&nbsp;Isabel L. Macêdo,&nbsp;Davi E. R. Sousa,&nbsp;Liz A. Cerqueira,&nbsp;Yasmin N. G. Fonseca,&nbsp;Ana L. V. Sousa,&nbsp;Antonio D. Santos,&nbsp;Cristiano B. de Melo,&nbsp;Márcio B. Castro","doi":"10.1002/ajp.70039","DOIUrl":"https://doi.org/10.1002/ajp.70039","url":null,"abstract":"<p>Electrical accidents pose a considerable threat to wildlife in anthropized regions, particularly arboreal mammals, as evidenced by cases of electrocutions in nonhuman primates (NHPs). This study characterized the frequency, anatomic distribution, and pathological features of electrocution injuries in free-ranging NHPs based on data retrieved from necropsy archives at the Veterinary Pathology and Forensics Laboratory, University of Brasilia, Brazil. Gross and microscopic evaluations were conducted to assess the nature and extent of electrothermal injuries, including burns and tissue damage. Between 2019 and 2022, electrocution accounted for 16.5% of NHP deaths, primarily affecting black tufted marmosets. Adult NHPs, regardless of sex, were predominantly affected, mainly in the rainy season. Limbs were the most commonly affected body parts, with double, triple, or multiple injury sites being common. Gross findings mostly included severe burns (Grades III and IV), ulcerative injuries, blisters, bone exposure, singed hair, and muscle exposure. Microscopic examinations unveiled epidermal necrosis, smudging of collagen fibers, stretched epidermal nuclei, blisters (epidermal honeycomb aspect), muscle necrosis, skin metallization, and hemorrhage and congestion within internal organs. Electrocution has emerged as a substantial cause of death in free-ranging NHPs, particularly in urban and peri-urban areas. The study underscores the need for public policy adjustments to mitigate the risks of electrocution in NHPs and enhance species conservation efforts in human-dominated landscapes.</p>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajp.70039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wild Chimpanzees (Pan troglodytes schweinfurthii) Use Tools to Access Out of Reach Water","authors":"Charlie MacKenzie,&nbsp;Skylar Brodnan,&nbsp;Elisa Felsche,&nbsp;Kris Sabbi,&nbsp;Emily Otali,&nbsp;Richard Wrangham,&nbsp;Alexandra G. Rosati,&nbsp;Zarin P. Machanda","doi":"10.1002/ajp.70036","DOIUrl":"https://doi.org/10.1002/ajp.70036","url":null,"abstract":"<div>\u0000 \u0000 <p>The use of tools to drink water is well-documented in wild chimpanzees, but the specific function of this behavior is unclear. Here we use a large data set of drinking behaviors spanning 14 years of observation from the Kanyawara community of chimpanzees living in Kibale National Park, Uganda, to test two possible functions of leaf-sponges and other drinking tools. On the one hand, chimpanzees may use tools to access water that is hard to reach, which predicts that chimpanzees will preferentially use tools to drink at tree holes and crevices compared to all other locations. Conversely, chimpanzees may use these tools to filter stagnant water, in which case they would use tools more often at holes and puddles compared to running water sources (e.g., streams). We compared both likelihood of using a tool to drink at different locations, as well as overall rates of drinking, and found chimpanzees in this community most often drink from streams without tools. However, when they do use tools, they preferentially do so to drink at tree holes. Given known age and sex effects on tool use in chimpanzees, we also examined demographic variation in drinking tool use to understand the emergence of this behavior. While females use tools more often than males overall—in part driven by differences in drinking rates at different locations—both males and females use tools more frequently at tree holes than other locations when they do drink there. Finally, comparisons by age indicate that this selectivity strengthens over development with older chimpanzees showing a more pronounced effect of using tools more often at tree holes, suggesting that younger chimpanzees may exhibit exploratory tool use behavior. These results pinpoint the specific function of tool use during drinking and further suggest that even simple tools may require learning for use in appropriate contexts.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pigtail Macaque (Macaca nemestrina) Performance Differs Across Multiple Cognitive Domains in Comparison to Rhesus Macaques (Macaca mulatta)","authors":"Isabella M. Baumann,&nbsp;Bess Carlson,&nbsp;Jasmine Hadeed,&nbsp;Suzanne E. Queen,&nbsp;Kenneth W. Witwer,&nbsp;Joseph Mankowski,&nbsp;Rebecca Veenhuis,&nbsp;Lydia M. Hopper","doi":"10.1002/ajp.70033","DOIUrl":"https://doi.org/10.1002/ajp.70033","url":null,"abstract":"<div>\u0000 \u0000 <p>Rhesus and pigtail macaques are closely related and have similar social structures, yet differences in their behavior, socio-ecology, and personality have been observed, although not systematically documented. Given these differences, it is important to assess pigtail macaque cognition independently, rather than relying on rhesus macaque findings as a proxy. To gain a better understanding of pigtail macaque cognition, we used a battery of three cognitive tasks. Rhesus macaques were tested on the same tasks to validate our methods and to allow for comparison. Across just three tasks, we found significant differences between the two closely related species. In the three cups task, which tests short-term memory, both pigtail and rhesus macaques performed significantly better when they had to recall the location of a hidden food reward after a 0 s delay compared to a 15 s delay. However, in the 15 s delay condition, only rhesus macaques performed above chance levels, whereas pigtail macaques did not. In the reversal learning task, which tested rule learning and cognitive flexibility, we found species differences in learning performance. For the quantity discrimination task, which tests numerosity, we found that both rhesus and pigtail macaques were more accurate at discriminating \"easy\" ratios of foods (e.g., 1 vs. 5 or 2 vs. 6) than the \"hard\" ratios (e.g., 2 vs. 3 or 4 vs. 5). However, pigtail macaques were more accurate than rhesus macaques in the hard ratio trials. These contribute to a novel understanding of cognition in pigtail macaques while also increasing research rigor in translational research.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Into the Fire: Problem-Solving and Pyrocognitive Behavior of Temple Dwelling Bonnet Macaques, Macaca radiata, in India","authors":"Mildred Berlena Blessy Herald Victor,&nbsp;Vinothini Govindharaj,&nbsp;Paul A. Garber,&nbsp;Parthasarathy Thiruchenthil Nathan","doi":"10.1002/ajp.70035","DOIUrl":"https://doi.org/10.1002/ajp.70035","url":null,"abstract":"<div>\u0000 \u0000 <p>Pyrocognition has been part of the hominin behavioral repertoire for at least one million years. Here, we report evidence of naturally occurring pyrocognitive behavior in wild bonnet macaques (<i>Macaca radiata</i>) inhabiting a temple site in India. We recorded 2704 instances of macaques attempting to extinguish the fire in offering lamps that contained a food reward (sesame seeds, rice flour, or coconut). Overall, we found significant variation associated with age, with adults experiencing higher foraging success (males 81.1% and females 75.3%) than subadults (males 30.1% and females 18.8%). In addition, there was a positive correlation between the number of lamp manipulations and foraging success among adults, but not among subadults. It appears that despite extensive exposure to burning lamps, subadult bonnet macaques failed to fully understand how their actions in attempting to extinguish the fire resulted in obtaining the food reward. In contrast, over time several adult bonnet macaques appeared to understand how their actions in extinguishing the fire resulted in successfully obtaining a food reward (i.e., causal knowledge). Our results indicate that pyrocognitive behavior develops slowly in bonnet macaques, differs between adults and subadults, is not sex-based, and provides an instructive model for pyrocognition in early hominins.</p></div>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143840841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Personality Assessment of Synanthropic Rhesus Macaques: Implications and Challenges","authors":"Taniya Gill,&nbsp;Anshul Gautam,&nbsp;Jorg J. M. Massen,&nbsp;Debottam Bhattacharjee","doi":"10.1002/ajp.70034","DOIUrl":"https://doi.org/10.1002/ajp.70034","url":null,"abstract":"<p>Answers to the question of what characteristics allow animals to thrive in human-dominated environments remain elusive. Consistent interindividual differences or personalities can potentially explain the functional significance of habitat-specific traits that enable animals to coexist with humans. Rhesus macaques (<i>Macaca mulatta</i>) are the most successful nonhuman primates in the Anthropocene, living in diverse climatic and environmental conditions. Studying the personalities of <i>synanthropic</i> rhesus macaques, that is, those that thrive in anthropogenic habitats, can provide insights into the biological traits facilitating their success. We planned a multi-method “bottom-up” approach of behavioral observations and novelty experiments, standardized for assessing captive nonhuman primates, to evaluate the personalities of adult rhesus macaques (<i>N</i> = <i>52</i>). Novelty experiments encountered significant challenges, limiting their effectiveness. So, we continued with behavioral observations in the form of focal sampling, that revealed two repeatable traits, subjectively labeled as <i>social tension</i> and <i>meekness</i>. We found an association of sex with social tension, where males exhibited higher social tension than females. In an additional analysis, we found that individuals that obtained food through contact provisioning had higher scores for the meekness trait than individuals that obtained food through noncontact provisioning. We discuss how the observed personality traits may offer adaptive advantages in human-dominated environments, where despotic rhesus macaques face both benefits and costs (including social) of living in an anthropogenic setting. We also emphasize that protocols designed for captive conditions may not be directly applicable to free-living animals. The study underscores the need to reconsider behavioral experiments to obtain comparable measures between captive and non-captive populations. This would enhance the ecological validity of personality assessments. Nevertheless, empirically identifying traits using observations in synanthropic species can provide valuable insights into the mechanisms that enable certain animals to thrive amidst a rapid expansion of anthropogenic activities.</p>","PeriodicalId":7662,"journal":{"name":"American Journal of Primatology","volume":"87 4","pages":""},"PeriodicalIF":2.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajp.70034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}