Biology subjects

Crofoot, M.

Publications and source records attributed to Crofoot, M..

5 recordsLinked to original sources

bioRxiv2026

Genetic and behavioural repertoires support olfactory communication in wild capuchin monkeys

Olfaction is a key sense for many mammals, but its role in the social lives of anthropoid primates (monkeys, apes, humans) is poorly understood. Studies of chemosensory receptor genes and olfactory behaviours can provide insight into the evolution and function of olfaction across social contexts. Vomeronasal receptor (VR) genes are especially relevant to social behaviour as they are specialized for the detection of pheromones and other cues involved in social signaling, reproductive behaviour, and individual recognition in mammals. Here, we examined the population genetics and gene repertoires of VR genes in wild white-faced capuchin monkeys (Cebus imitator) from Costa Rica and Panama using DNA sourced through both host tissues and through noninvasive fluorescence-activated cell sorting of fecal samples (fecalFACS). We compared VR diversity relative to putatively neutral reference loci (NRs) to investigate evidence of selection and potential effects of demography. To complement the genetic analysis, we also conducted a detailed observational study of capuchin olfactory behaviours. Combined, we find evidence of intact VRs subject to evolutionary constraint in capuchins, providing novel evidence that members of this gene family are maintained by evolutionary constraint in wild monkeys. We further document a rich and varied ethogram of olfactory behaviours that have clear potential for communication. Overall, our study provides compelling evidence for a role of olfaction in the complex social lives of capuchin monkeys, motivating future research on the contributions of olfaction to social communication and evolution in primates and other mammals.

animal behavior and cognition↗

bioRxiv2025

White-faced capuchins (Cebus capucinus imitator) exhibit selectivity for stone tools

Over the last few decades, the developing field of primate archaeology has used archaeological methods to reconstruct primate behaviors, especially tool use. We expand the possibilities of primate archaeology with an inverse approach: using living primates to address archaeological questions. In particular, we investigate tool selectivity, a phenomenon that not only represents a significant milestone for tool users, also for the emergence of stone tool technology in human evolution. Observing extant primate tool use can establish clear expectations for a percussion-based archaeological record across taxa. Here, we describe stone tools assemblages produced by two independent populations of white-faced capuchin monkeys (Cebus capucinus imitator) in Coiba National Park, Panama, and provide evidence of stone tool selectivity in both populations. We demonstrate that capuchins select for tool dimensions, and select different sizes for different tool functions. This selectivity analysis reveals that primate stone tool use results in assemblages of artifacts that are distinct from natural accumulations of unused material in the surrounding landscapes. These variations further suggest that stone tool use has a recognizable signature at the assemblage level, even where no lithic flaking occurs. The existence of such assemblage-level signatures offer new avenues for the archaeological identification of tool use both in unhabituated living primates and extinct taxa. The presence of selectivity in multiple capuchin populations suggests that, along with percussion, tool selectivity is ancestral to stone tool flaking, and is shared by phylogenetically distant branches of the primate tree.

animal behavior and cognition↗

bioRxiv2024

Consistent long-distance foraging flights across years and seasons at colony level in a Neotropical bat

All foraging animals face a trade-off: how much time should they invest in exploitation of known resources versus exploration to discover new resources? For group-living central place foragers, balancing these competing goals poses particular challenges. The availability of social information may discourage individuals from investing in risky, expensive but possibly rewarding exploration. We GPS-tracked groups of greater spear-nosed bats (Phyllostomus hastatus) from three colonies on Isla Colon in Panama. In the dry season, when these omnivores forage on the nectar of ephemeral balsa flowers (Ochroma pyramidale), bats consistently travelled long distances to remote, colony-specific foraging areas, bypassing flowering trees closer to their roosts. They continued to use these same areas in the wet season, when feeding on a diverse, presumably ubiquitously distributed diet, but also visited other, similarly distant foraging areas. Foraging areas were shared within, but not always between colonies. Our longitudinal dataset suggests that bats from each colony invest in long-distance commutes to socially learned shared foraging areas, bypassing other available food patches. Rather than investing in exploration to find nearby resources or engaging in a win-stay lost-shift foraging strategy, these bats follow colony specific behaviours consistent with the existence of culturally transmitted preferences for specific feeding grounds.

animal behavior and cognition↗

bioRxiv2023

Estimating individuals' exposure to predation risk in group-living baboons, Papio anubis

In environments with multiple predators, the vulnerabilities attached to the spatial positions of group-living prey are not uniform and depend on the hunting styles of the predators. Coursing predators, mainly canids and hyenas, follow their prey over long distances and attack open areas, making individuals at the edge of the group more dangerous than those at the center (marginal predation). In contrast, ambush predators, mainly cats, approach their prey undetected and appear randomly anywhere in the group; therefore, isolated individuals are at a greater risk of predation. However, identifying individuals at high risk of predation requires the simultaneous recording of predator locations and direct observation of predation events, which are both difficult. Therefore, several theoretical methods have been proposed to assess predation risk (predation risk proxies). In a group of wild anubis baboons exposed to predation by leopards, lions, and hyenas, we calculated predation risk proxies using movement data collected from global positioning system (GPS) collars and found that adult males were on the edge of the group with a higher risk of predation (Hypothesis 1). In addition, adult males were more isolated within this group (Hypothesis 2). None of the predation risks differed among the other age-sex classes. The most dominant male was expected to be in the safety center of the group (Hypothesis 3) but was isolated on the periphery, like the other males. Therefore, we discussed why adult males were more peripheral and isolated.

zoology↗

bioRxiv2021

Animal lifestyle changes acceptable mass limits for attached tags

O_LIAnimal-attached devices have transformed our understanding of vertebrate ecology. To minimize tag-related harm for these studies, researchers have long advocated that tag masses should not exceed 3% of the animals body mass. However, this proposition ignores tag forces generated as a result of animal movement. C_LIO_LIUsing data from collar-attached accelerometers on diverse free-ranging terrestrial animals, we detail a tag-based acceleration method (TbAM) in which we quantify animal athleticism in terms of fractions of animal movement time devoted to different collar-recorded accelerations. The varying accelerations are converted to forces imposed on the animals based on the acceleration and tag mass and allow derivation of defined force limits, including those amounting to 3% of the animals mass, for specified fractions of any animals active time. C_LIO_LIWe demonstrate how species athleticism is the principal determinant of tag forces, whereas body mass is of little importance. Forces exerted by 3% tags were mostly equivalent to 4-19% of the animals masses during moving, with a maximum of 54% in a hunting cheetah. Cumulative frequency curves of tag acceleration for periods when animals were active, all showed a characteristic sigmoid pattern, which was displaced further to the right as higher acceleration activities accounted for an increasing proportion of any animals time. Specifying that tags should exert forces that are less than 3% of the animals body mass for 95% of the time led to corrected tag masses constituting between 1.6% and 2.98% of our study animals masses, with values depending on animal athleticism. C_LIO_LIRecognition that animal athleticism affects tag forces of their carriers fundamentally changes how acceptable tag mass limits should be determined by ethics bodies. In order to have a scientifically robust acceptable threshold to limit the forces experienced by an animal carrier, we suggest practitioners derive a similar cumulative acceleration profile for their study species and use a minimum of the 95% limits on the plot (although higher limits may be more appropriate). C_LI

zoology↗