Positional behavior and substrate use in wild adult bearded capuchin monkeys ( Sapajus libidinosus )

Terrestriality across the primate order: A review and analysis of ground use in primates

Terrestriality is relatively rare in the predominantly arboreal primate order. How frequently, and when, terrestriality appears in primate evolution, and the factors that influence this behavior, are not well understood. To investigate this, we compiled data describing terrestriality in 515 extant nonhuman primate taxa. We describe the geographic and phylogenetic distribution of terrestriality, including an ancestral state reconstruction estimating the frequency and timing of evolutionary transitions to terrestriality. We review hypotheses concerning the evolution of primate terrestriality and test these using data we collected pertaining to characteristics including body mass and diet, and ecological factors including forest structure, food availability, weather, and predation pressure. Using Bayesian analyses, we find body mass and normalized difference vegetation index are the most reliable predictors of terrestriality. When considering subsets of taxa, we find ecological factors such as forest height and rainfall, and not body mass, are the most reliable predictors of terrestriality for platyrrhines and lemurs.

Easy to gain but hard to lose: the evolution of the knee sesamoid bones in Primates-a systematic review and phylogenetic meta-analysis

Sesamoids are variably present skeletal elements found in tendons and ligaments near joints. Variability in sesamoid size, location and presence/absence is hypothesized to enable skeletal innovation, yet sesamoids are often ignored. Three knee sesamoids-the cyamella, medial fabella and lateral fabella-are present in primates, but we know little about how they evolved, if they are skeletal innovations, or why they are largely missing from Hominoidea. Our phylogenetic comparative analyses suggest that sesamoid presence/absence is highly phylogenetically structured and contains phylogenetic signal. Models suggest that it is easy to gain but difficult/impossible to lose knee sesamoids and that the fabellae may have similar developmental/evolutionary pathways that are distinct from the cyamella. Sesamoid presence/absence is uncorrelated to the mode of locomotion, suggesting that sesamoid biomechanical function may require information beyond sesamoid presence, such as size and location. Ancestral state reconstructions were largely uninformative but highlighted how reconstructions using parsimony can differ from those that are phylogenetically informed. Interestingly, there may be two ways to evolve fabellae, with humans evolving fabellae differently from most other primates. We hypothesize that the 're-emergence' of the lateral fabella in humans may be correlated with the evolution of a unique developmental pathway, potentially correlated with the evolution of straight-legged, bipedal locomotion.

Insights into the evolutionary history of the most skilled tool-handling platyrrhini monkey: Sapajus libidinosus from the Serra da Capivara National Park

Sapajus libidinosus members of the Pedra Furada group, living in the Serra da Capivara National Park, use stone tools in a wider variety of behaviors than any other living animal, except humans. To rescue the evolutionary history of the Caatinga S. libidinosus and identify factors that may have contributed to the emergence and maintenance of their tool-use culture, we conducted fieldwork seasons to obtain biological samples of these capuchin monkeys. UsingCYTBsequences, we show a discrete but constant population growth from the beginning of the Holocene to the present, overlapping the emergence of the Caatinga biome. Our habitat suitability reconstruction reports the presence of plants whose hard fruits, seeds, or roots are processed by capuchins using tools. TheS. libidinosusindividuals in the Caatinga were capable of dynamically developing and maintaining their autochthonous culture thanks to: a) cognitive capacity to generate and execute innovation under selective pressure; b) tolerance favoring learning and cultural inheritance; c) an unknown genetic repertoire that underpins the adaptive traits; d) a high degree of terrestriality; e) presence and abundance of natural resources, which makes some places "hot spots" for innovation, and cultural diversification within a relatively short time.

Factors influencing terrestriality in primates of the Americas and Madagascar

Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use.

Feeding postural behaviors and food geometric and material properties in bearded capuchin monkeys ( Sapajus libidinosus )

Objectives

Foods that are geometrically and mechanically challenging to eat have been associated with specializations in feeding behavior and craniodental morphology across primates, and many of these foods are embedded, requiring a variety of positional behaviors during feeding. However, variation in positional behaviors in response to food properties is not well understood. Here, we examine differences in feeding postural behaviors across feeding events in relation to substrate and food geometric and material properties in a species of extractive foragers, bearded capuchins (Sapajus libidinosus).

Methods and materials

We coded over 1400 co‐occurring postural and feeding behaviors, their durations, and relative sizes of substrate and food from videos recorded at Fazenda Boa Vista in Gilbués, Piauí, Brazil. Food material properties were measured from foods collected at the time of the video recordings.

Results

Our results suggest that bearded capuchin feeding postures significantly differ across the feeding sequence, with substrate size, and between foods of high and low toughness and elastic modulus. Feeding postures were less variable for highly mechanically challenging foods. Food size also had a significant effect on postural behaviors. Large foods were more likely to be associated with suspended postures and small foods with sitting and squatting. Feeding postural behaviors were best explained by a combination of substrate and food variables.

Conclusions

Our results indicate that food geometric and mechanical properties have a significant influence on feeding postural behaviors in bearded capuchins. We posit that feeding postural behaviors reflect a combination of substrate variables and food properties, and large, mechanically challenging foods have a limiting effect on postural variation.

Positional Behavior and Substrate Use in Wild Tibetan Macaques

Body size and individual development significantly affect positional behavior and substrate use. However, only a few studies have been conducted on immature wild macaques. We studied wild Tibetan macaques (Macaca thibetana) inhabiting Mt. Huangshan, China, to explore the degree of interspecific variation in positional behavior in relation to body weight and individual development. From September 2020 to August 2021, we used instantaneous scan sampling (duration 5 min, interval 10 min) to record age–sex groups, locomotions, postures, and substrate attributes. The results showed that Tibetan macaques used terrestrial substrates in nearly two-thirds of the recorded observations. The main postural modes were sitting and quadrupedal standing. The main locomotor modes were quadrupedal walking and climbing among all age–sex group records. Positional behavior and substrate use in adults only significantly differed from those in juveniles and infants. Although adult males were larger than the other age–sex groups, they did not climb and bridge more frequently than the other age–sex groups. The frequency of climbing, leaping, and suspension was significantly higher in juveniles than in adults. In addition, adult males used terrestrial and larger substrates more frequently, while juveniles and infants used arboreal substrates and terminals more frequently than adult males during traveling and feeding. We hypothesize that the more positional behavioral spectrum of Tibetan macaque juveniles’ may be related to rapid skeletal muscle development. These results suggest that differences in interspecific positional behavior may be caused by the individual development and survival needs of individuals, rather than just body size.

Comparative anatomy of the encephalon of new world primates with emphasis for the Sapajus sp

Studies about the anatomy of the New World Primates are scarce, mainly comparative neuroanatomy, then a morphological comparative analysis about the tropical Primates were performed and a effort was made for an Old World Primates and modern humans relationship for the obtained data; plus, comments about behavior e and allometry were performed to try link the high cognition and abilities of the Sapajus with the neuroanatomical results, however, despite the deep neuroanatomic data obtained, we do not found an intrinsic relation to explain that.

Anticipating future actions: Motor planning improves with age in wild bearded capuchin monkeys (Sapajus libidinosus)

Self-directed object manipulation tasks illuminate development of motor planning. Grasping strategies that lead to good object control to perform the following action(s) reveal second-order motor planning. Motor planning for efficient grips develops slowly in children. Age-related differences in other primates have been poorly investigated. Here, we investigated anticipatory motor planning of infant, juvenile and adult wild capuchin monkeys grasping a horizontally positioned stick baited to the left or right side (a version of the elevated spoon task). We recorded the grasps capuchins used to bring the baited end of the stick to the mouth. The percentage of efficient radial grips positively correlated with age and adults used efficient grips significantly more frequently than infants. Adult wild capuchins' use of radial grips was higher than that reported for adult captive capuchins in similar tasks, suggesting that experience throughout life may influence motor anticipation. Self-directed object manipulation tasks will be useful to compare this aspect of cognition across primates. A video abstract of this article can be viewed at https://youtu.be/a1Zbr_AQkb8.

Isotopic and elemental corroborates for wild bearded capuchin (Sapajus libidinosus) omnivorous dietary adaptation at Fazenda Boa Vista, Brazil

RATIONALE

This study analyzes variability in the diets of wild bearded capuchin monkeys, Sapajus libidinosus, by analyzing stable carbon (δ¹³ C) and nitrogen (δ¹⁵ N) isotope ratios and elemental concentrations (%C and %N) of fecal samples and food items. Developing isotopic and elemental correlates for diets of habituated subjects is a necessary step towards applying similar methods to interpret diets of unhabituated or cryptic subjects.

METHODS

Fecal samples from wild capuchins and their foods were collected at Fazenda Boa Vista, Brazil. Fecal samples from laboratory-housed Sapajus spp. and their foods were analyzed to establish diet-feces offsets for δ¹³ C, δ¹⁵ N, %C, and %N. Samples were dried, powdered, and measured for isotopic and elemental values. A Bayesian mixing model commutes isotopic and elemental data from wild capuchins into likely proportions of different food categories.

RESULTS

The captive study shows small diet-feces spaces for Sapajus spp. of -0.8 ± 0.7‰ for δ¹³ C, -0.2 ± 0.4‰ for δ¹⁵ N, -6.1 ± 1.7% for %C, and -1.0 ± 0.6% for %N. The wild study shows omnivorous diets based on C₃ , C₄ , and CAM plants, and fauna. Subject diets are highly varied within and between days. Fecal data show age-related differences in diet and crop-raiding. There is no consistent isotopic or elemental difference between mothers and infants.

CONCLUSIONS

Fecal stable isotope and elemental evidence employed in a Bayesian mixing model reflects the highly varied diets of capuchin monkeys in an isotopically heterogeneous environment. The isotopic and elemental variability reported here will aid similar diet reconstructions among unhabituated subjects in the future, but precludes tracking weaning isotopically among capuchins in this environment.