Seasonal resource categorisation and behavioral adaptation among chimpanzees: Implications for early hominin carnivory

Abstract

Seasonality plays a critical role in determining the yearly dietary variability of many nonhuman primates living in tropical and subtropical environments. Much previous research has emphasised the seasonal importance of both preferred resources—eaten whenever available—and fallback foods—eaten during periods of scarcity to compensate for an insufficient availability of preferred resources. However, previous discussions of this dichotomy have often overlooked why different populations of the same taxon may exhibit a different level of engagement with identical resources, especially those that require some degree of technological investment by virtue of being embedded. Similarly, not enough attention has been given to diachronic trends in the incorporation of novel resources to seasonal consumption patterns among non-human primates.In this paper, we present a framework for understanding the spatio-temporal relationships between preferred and fallback resources in a more systematic way, explicitly through the lens of landscape knowledge and seasonal fluctuations in quality and availability. We argue it is the interplay between resource quality and the available knowledge pertaining to its exploitation that will determine the categorisation of a resource. In this regard, the accumulation of further information through encounter, experimentation, and behavioural (including technological) innovation enables resources with high nutritional potential to attain preferred status. We end with an exploration of the gradual consolidation of the hominin carnivory niche in the Early Pleistocene of East Africa, to demonstrate the utility of our framework—specifically the interplay between seasonality and the concept of landscape knowledge—for understanding behavioural change in the archaeological record.