Diet, activity patterns, and home range use in forest and cultivated areas for one wild group of endangered crested capuchin monkeys (Sapajus robustus) in Reserva Natural Vale, Espírito Santo, Brazil

Abstract

Robust capuchin monkeys (Sapajus spp.) are distributed widely in the Neotropics and may be able to survive in modified landscapes because of their omnivorous, opportunistic diet. The poorly known and endangered crested capuchin monkey (Sapajus robustus) is endemic to the Atlantic Forest in Bahia, Minas Gerais and Espírito Santo states, Brazil. We collected data on diet and home range for a crested capuchin group with access to forest and cultivated areas. We hypothesized that with access to cultivated exotic fruit, capuchins would use cultivated areas more for feeding during the season of fruit scarcity in the surrounding forest and have a small home range size because of higher fruit availability. Both the forest and the cultivated areas peaked in fruit availability in the wet season, with a low proportion of trees producing fruit in the dry season; cultivated areas had a higher proportion of trees in fruit compared to the forest throughout the study. While monkeys consumed exotic fruits like jackfruit and oil palm, we recorded more samples of them eating forest fruits than exotic fruits in all but 1 month, and they consumed a more diverse array of forest fruits (56 species) but only six exotic species. Home range size was relatively small compared with other studies: 120.5 ha across the year (wet season 102 ha, dry season 111.5 ha). Natural and human‐intensified fruit sources in a protected area without hunting may have allowed monkeys to maintain a smaller home range size. The group composition changed during the study; this also likely influenced home range use. Studies focused on robust capuchin groups that utilize agricultural or cultivated foods may underestimate home range needs for groups without access to human‐intensified food sources. Studying crested capuchin ecology in additional locations will be important for establishing a sound species conservation program.

A robust tool kit: First report of tool use in captive crested capuchin monkeys (Sapajus robustus)

“…We predict that at least some wild crested capuchins use tools. Due to their Atlantic Forest habitat, crested capuchins are surrounded with raw materials and likely experience marked seasonal variation in fruit availability (Martins et al, 2022; Spagnoletti et al, 2012), both of which contribute to the opportunity to create tools for solving foraging challenges. Furthermore, as a gregarious primate, the ample raw materials allow for the opportunity of tool‐mediated social interaction such as throwing and waving.…”

“…This phenomenon of intergroup variation in tool use can be seen in S. xanthosternos (Canale et al, 2009), the species most closely related to S. robustus (Lima et al, 2018; Lynch Alfaro et al, 2012). The single‐year‐long research study to date of wild crested capuchins (Martins, 2010; Martins et al, 2022) may have simply observed by chance a group that did not use tools, and the species remains severely understudied. Even in populations where tool use does not occur, individuals in this species may be using their manual and cognitive skills to deal with other complex challenges.…”

“…Even in populations where tool use does not occur, individuals in this species may be using their manual and cognitive skills to deal with other complex challenges. As the human population increases, crested capuchins, an endangered species whose population is declining (Martins et al, 2017(Martins et al, , 2021, find themselves in novel anthropogenic environments subject to fragmentation (Martins et al, 2022;Mota et al, 2018). Studies examining how crested capuchins respond and adapt to these novel environments, and documenting diversity in behaviors such as tool use across different populations, are sorely needed for this understudied and endangered species.…”

“…One obvious reason for the absence of tool use reports might simply be the lack of research on this particular species. Thus far, there has only been a single year‐long research study of wild crested capuchins, with no accounts of tool use described amongst 15 individuals in over 370 observation hours (Martins et al, 2022; Martins, 2010). Of note is that S. robustus diverged from its sister taxon, S. xanthosternos , over 2 million years ago (Lima et al, 2018)—as much or more time depth as the divergence between bonobos and chimpanzees, sister species that are extremely different in their tool use behavior (Furuichi et al, 2015).…”

Observations on the diet of Aotus nigriceps (Primates: Cebidae) in an urban and peri-urban area in Rondônia state, Brazil

“…Thus, the exploitation of exotic species could be an adaptation to altered environments, and a response to anthropogenic changes. Martins et al (2022) studying Sapajus robustus recorded the use of six cultivated exotic species, which may have favored the maintenance of a smaller home range when compared to other conspecifics and congenerics. This consumption of exotic cultivated food sources can lead to conflicts between humans and wildlife, as losses in harvest could be attributed to primates or other species.…”