American Journal of Primatology最新文献

The Cayo Santiago rhesus colony and its derived skeletal collections provide abundant data made available since its founding in 1938. A project supported by an NSF collaborative grant has been committed to building a database that integrates the genetic and age-related information of the colony, together with social group interactions and environmental effects, aiming to provide a knowledge model to researchers with insights from this powerful non-human data repository for analyzing human conditions including growth, development, adaption, resilience, aging, and disease in a contextualized manner. This paper introduces CSViewer for Analysts, a computer application that provides user-friendly tools for researchers to access the integrated database and to generate a variety of visuals encompassing matrilineal or patrilineal family lines, social groups, time spans, phenotypic measurements, and photos recently collected through this project. Adopting Java-based technologies and third-party libraries for data analytics and visualization, CSViewer can help its users select meaningful datasets using various criteria, conduct data analytics and visualization tasks, and manage their “project artifacts” (such as selected datasets, models, and charts, etc.). Version 1.0 of the CSViewer app has been tested by collaborators and in a workshop by a limited number of researchers and science educators since 2023. Based on users' feedback, additional features have been implemented in version 1.1.0, and more features are planned for subsequent subversions with bundles for researchers to download and explore.

The nighttime behavior of diurnal species is a “black box.” Although diurnal animals spend approximately half their lives in the dark, research has, for too long, relied on the simplifying assumption that what we can't observe isn't important. Advances in our ability to monitor nighttime behavior reveal that this is incorrect; essential biological and behavioral processes play out in the dark which are critical for understanding a species' ecology and evolution. We conducted our study from November 2021 to January 2022, using noninvasive 4G solar-powered night-vision cameras to quantitatively assess the impact of environmental and social factors on the diel activity patterns of wild Tibetan macaques at Mt. Huangshan, China. We find that Tibetan macaques maintain high levels of sleep throughout the night, as is typical for diurnal animals. However, non-sleep activity still accounted for 18.28% ± 0.45% of the total nighttime period, with activity occurring throughout the night. Notably, there was a peak in activity at midnight, including resting, movement, and social. Low temperatures significantly reduced daytime activity levels, while increasing nighttime activity, indicating that extreme temperatures have divergent impacts on activity levels during the day versus the night. Additionally, social activities were more frequent among females during the day, whereas males were more socially active at night. The distinct patterns of social activities during the day and night highlight the crucial role of social factors in nocturnal activities. The night-vision cameras have proven to be an effective research tool, allowing for a deeper understanding of primate behavior patterns and social structures. This provides new avenues for future research into the drivers of nighttime behavioral patterns across species.

Colors are an important signal for many primate species and have the potential to influence behavior and cognition. Primates may consciously or unconsciously prioritize their attention toward certain color stimuli to quickly identify consequential events, conspecifics, or resources. On the other hand, primates' color preferences can be modulated by memory, experiences, and affective responses. Few studies have explored the multifaceted nature of attention to colors in primate species that vary in their socioecologies and phenotypes, both of which may influence their responses to specific colors. The colors that rapidly capture primates' attention, and those they prefer, thus remain poorly understood. In a series of touchscreen experiments, we investigated responses to 9 perceptually distinct colored squares by 7 chimpanzees (Pan troglodytes), 11 gorillas (Gorilla gorilla gorilla), and 10 Japanese macaques (Macaca fuscata). We controlled for contextual cues known to influence color responses and assessed attentional biases using a dot probe task (Experiment 1) and preferences using a two-item forced-choice task (Experiments 2 and 3). In Experiment 1, we found that chimpanzees and gorillas showed the strongest attentional bias toward black, whereas the Japanese macaques showed the strongest bias toward red. These attentional biases suggest a potential relationship between species coloration and their attention to colors. In Experiments 2 and 3, all three species preferentially selected red, with Japanese macaques showing the strongest preference, supporting earlier findings that highlighted red as a particularly salient color to primates. Future research is needed to investigate the role of prior experience on primates' responses to colors.

Traditional qualitative behavioral assessments (QBAs) employ a unique whole-animal approach to measure animal welfare with a focus on affective elements. QBAs require comprehensive validation including reliability across multiple raters, subjects, and institutions, as well as consistency with other validated assessment measures. In 2016, the Detroit Zoological Society developed and began internally validating the Gorilla Behavioral Assessment Tool (GBAT), followed by internal applications of a revised GBAT in 2021. This study continues these validation efforts through the multi-institutional application of the GBAT in baseline conditions. Five zoological institutions participated in this study, creating a study population of 15 adult male western lowland gorillas (Gorilla gorilla gorilla) and more than 40 staff. Care staff collected fecal samples from each gorilla, and two staff from each institution completed the GBAT for each gorilla daily. Three of the five institutions collected focal behavioral data. We calculated inter-rater reliability using Gwet's AC₂, establishing near-perfect reliability across all tested items. We found no significant variation in reliability between institutions. We used the behavioral data and fecal glucocorticoid metabolites for construct validation. A combination of Spearman's correlations and generalized linear mixed models demonstrated statistically significant relationships between seven of the 12 tested GBAT items and other established measures. Integration of physical and behavioral indicators of welfare alongside affective indicators alters the GBAT from a traditional QBA into what we propose as a mixed or M-QBA. Our work demonstrates how an M-QBA allows for a more comprehensive assessment of animal welfare with implications for broader research applications.

Rhesus macaques (Macaca mulatta) have long been used as a model for the evolution of some aspects of human social behavior and they are among the most completely understood species of the macaque genus. Rhesus macaques have a despotic dominance hierarchy with a well-documented facial display repertoire. However, we know little about the ontogenetic changes in gross facial musculature and how this might relate to corresponding facial display behavior. In an effort to illuminate our understanding, we dissected facial masks from 13 M. mulatta cadavers that died naturally, shortly after birth or were stillborn, and we compared these results to those from adult rhesus macaques. Results reveal that, unlike the adults in the present study, infant rhesus macaques have extrinsic external ear muscles and muscles associated with the lower lip that are very gracile and poorly developed. Musculature associated with the upper lip and nares are well developed, individually distinct, and robust, like those of the adults in our sample and adult M. mulatta. However, we were unable to locate the zygomaticus major muscle in any fetal/infant sample. These results may reflect simple variation in mimetic muscle ontogeny, differences related to facial allometry, or they could reflect a behaviorally meaningful adaptation to different life stages of macaque ontogeny.

Laboratory studies have broadened our understanding of primate arboreal locomotor biomechanics and adaptation but are necessarily limited in species availability and substrate complexity. In this field study, we filmed the locomotion of 11 species of platyrrhines (Ecuador and Costa Rica; n = 1234 strides) and remotely measured substrate diameter and orientation. We then explored ecological and phylogenetic influences on quadrupedal kinematics in multivariate space using redundancy analysis combined with variation partitioning. Among all species, phylogenetic relatedness more strongly influenced quadrupedal kinematics than variation in substrate. Callitrichines were maximally divergent from other taxa, driven by their preferred use of higher speed asymmetrical gaits. Pitheciids were also distinctive in their use of lower limb phases, including lateral sequence gaits. The biomechanical implications of interspecific differences in body mass and limb proportions account for a substantial portion of the phylogenetic-based variation. Body mass and kinematic variation were inversely related–whereas the larger taxa (atelids) were relatively restricted in kinematic space, and preferred more stable, symmetrical gaits, the smallest species (callitrichines) used faster, more asymmetrical and less cautious gaits along with symmetrical gaits. Intermembral index had a positive relationship with limb phase, consistent with higher limb phases in atelines compared to pitheciids. Substrate alone accounted for only 2% of kinematic variation among all taxa, with substrate orientation influencing kinematics more than diameter. Substrate effects, though weak, were generally consistent with predictions and with previous laboratory and field-based research. Excluding callitrichines and asymmetrical gaits, the influence of substrate alone remained low (2%), and the phylogenetic signal dropped from 31% to 8%. The substantial residual kinematic variation may be attributable to substrate or morphological variables not measured here, but could also reflect basic biomechanical patterns shared by all taxa that serve them well when moving arboreally, regardless of the challenges provided by any particular substrate.