Stone tool use in wild bearded capuchin monkeys, Cebus libidinosus. Is it a strategy to overcome food scarcity?
Publication Type: |
Journal Article |
Year of Publication: |
2012 |
Authors: |
N. Spagnoletti, E. Visalberghi, M.P. Verderane, E. Ottoni, P. Izar, D. Fragaszy |
Publication/Journal: |
Animal Behaviour |
Keywords: |
*tool use, bearded capuchin, cebus libidinosus, fallback food, necessity hypothesis, nut cracking, opportunity hypothesis |
ISBN: |
00033472 |
Abstract:
To determine whether tool use varied in relation to food availability in bearded capuchin monkeys, we
recorded anvil and stone hammer use in two sympatric wild groups, one of which was provisioned daily,
and assessed climatic variables and availability of fruits, invertebrates and palm nuts. Capuchins used
tools to crack open encased fruits, mostly palm nuts, throughout the year. Significant differences
between wet and dry seasons were found in rainfall, abundance of invertebrates and palm nuts, but not
in fruit abundance. Catulè nuts were more abundant in the dry season. We tested the predictions of the
necessity hypothesis (according to which tool use is maintained by sustenance needs during resource
scarcity) and of the opportunity hypothesis (according to which tool use is maintained by repeated
exposure to appropriate ecological conditions, such as preferred food resources necessitating the use of
tools). Our findings support only the opportunity hypothesis. The rate of tool use was not affected by
provisioning, and the monthly rate of tool use was not correlated with the availability of fruits and
invertebrates. Conversely, all capuchins cracked food items other than palm nuts (e.g. cashew nuts) when
available, and adult males cracked nuts more in the dry season when catulè nuts (the most common and
exploited nut) are especially abundant. Hence, in our field site capuchins use tools opportunistically