Habitual stone-tool-aided extractive foraging in white-faced capuchins,Cebus capucinus

Abstract

Habitual reliance on tool use is a marked behavioural 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. rarely use tools and have never been observed using stone tools. By contrast, habitual tool use by Sapajus is widespread. We review theory and 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 behaviour has persisted on one island in Coiba National Park since at least 2004. From 1 year of camera trapping, we found that stone tool use is strongly male-biased. Of the 205 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 behaviour. Stone tool use occurs year-round in this population; 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.

Naïve orangutans (Pongo abelii & Pongo pygmaeus) individually acquire nut-cracking using hammer tools

“…So far, capuchins ( Cebus apella, Cebus capucinus imitator, Sapajus libidinosus ), chimpanzees ( Pan troglodytes ), long-tailed macaques ( Macaca fascicularis aurea ) and humans ( Homo sapiens ) have all been observed using tools to crack nuts (Barrett et al, 2018; Boesch et al, 1994; Haslam, Cardoso, Visalberghi, & Fragaszy, 2014; Luncz et al, 2017; Morgan & Abwe, 2006; Ottoni & Mannu, 2001; Parker & Gibson, 1977; Pfungst, 1912). The data on nut-cracking across primate species suggests that this behaviour may have also been present in the last common ancestor between modern human and great apes (Neadle et al, 2002).…”

Exploring the role of individual learning in animal tool-use

“…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). Furthermore, other factors, such as the environment, genetics, pre-existing techniques and other cognitive abilities all contribute to the likelihood of a behaviour being reinnovated.…”

“…The importance of these factors, alongside recognising the equifinality of behaviours (i.e. behaviours can emerge via different mechanisms, or a combination of various mechanisms, across individuals; Barrett et al, 2018), should not be neglected. The findings of this review suggest that whilst individual learning and non-copying social learning mechanisms are widespread across animal species, and indeed we should perhaps assume a priori that most animals do acquire some of their information 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

“…[177][178][179] The field offers a wide range of variability. 48,180 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.…”

“…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. [46][47][48] Unfortunately, the number of cognitive abilities that have been studied in the same primate species, both in the field and the lab, can often be counted on two hands. For example, regarding studies that investigated whether chimpanzees are able to plan for the future, defined as acting for a future motivational state, 22 I counted seven studies from captivity (observational 49,50 : 2; experimental 51-55 : 5), and only one from the wild (observational: 1, 19 experimental: 0).…”