Habitual Stone-Tool Aided Extractive Foraging in White-Faced Capuchins, Cebus Capucinus

Abstract

Habitual reliance on tool use is a marked behavioral difference between wild robust (genus Sapajus) and gracile (genus Cebus) capuchin monkeys. Despite being well studied and having a rich repertoire of social and extractive foraging traditions, Cebus sp have rarely been observed engaging in tool use and have never been reported to use stone tools. In contrast, habitual tool use and stone-tool use by Sapajus is widespread. We discuss factors which might explain these differences in patterns of tool use between Cebus and Sapajus. We then report the first case of habitual stone-tool use in a gracile capuchin: a population of white-faced capuchins (Cebus capucinus imitator ) in Coiba National Park, Panama who habitually rely on hammerstone and anvil tool use to access structurally protected food items in coastal areas including Terminalia catappa seeds, hermit crabs, marine snails, terrestrial crabs, and other items. This behavior has persisted on one island in Coiba National Park since at least 2004. From one year of camera trapping, we found that stone tool use is strongly male-biased. Of the 205 unique camera-trap-days where tool use was recorded, adult females were never observed to use stone-tools, although they were frequently recorded at the sites and engaged in scrounging behavior. Stone-tool use occurs year-round in this population, and over half of all identifiable individuals were observed participating. At the most active tool use site, 83.2% of days where capuchins were sighted corresponded with tool use. Capuchins inhabiting the Coiba archipelago are highly terrestrial, under decreased predation pressure and potentially experience resource limitation compared to mainland populations-three conditions considered important for the evolution of stone tool use. White-faced capuchin tool use in Coiba National Park thus offers unique opportunities to explore the ecological drivers and evolutionary underpinnings of stone tool use in a comparative within-and between-species context.

Object grasping and manipulation in capuchin monkeys (genera Cebus and Sapajus)

“…Moreover, it is an example of tool use, because capuchins pound the dry nuts placed on a hard surface (stone or wood) by using a stone as a percussor (Sirianni & Visalberghi, 2013). Percussive tool use occurs in a very limited number of mammals, and is seen particularly in tufted capuchins (but see Barrett et al, 2018 for recent findings in untufted capuchins), chimpanzees (Boesch & Boesch-Achermann, 2000;Matsuzawa, 2011) and macaques (Gumert & Malaivijitnond, 2013). As we will see below, capuchins are flexible tool users, using many different types of tools to reach a wide variety of goals (Visalberghi et al, 2017).…”

Peer Review #2 of "Exploring the role of individual learning in animal tool-use (v0.1)"

“…Although individual learning may play an important role in encouraging the emergence of novel behaviours, it is the combination of individual learning and the various types of non-copying social learning that allow for the successful sustenance of the rich animal tool-use behavioural repertoires (Reader & Laland, 2003;Barrett et al, 2018;Heyes, 2011). Manuscript to be reviewed of their information influenced via non-copying social learning, the evidence for form copying social learning in most animal species is much less clear.…”

What animals do not do or fail to find: A novel observational approach for studying cognition in the wild

“…For this, it is essential to study the capacities of populations that live in different environmental conditions . The field offers a wide range of variability . Hence, comparative studies on cognitive performances of wild and captive animals provide a wealth of opportunities to determine which factors are important for the development of particular cognitive skills.…”

“…Variables so far identified are: (a) time available for exploration of objects, (b) frequency of access to objects, and (c) levels of distraction (by predation risk or a need to search for food). Acknowledging these variables and linking them to ecological variables, such as food availability, provides useful guidelines when designing statistical models that investigate why some natural populations of primates use tools in some habitats, but not in other habitats …”