Seasonality and Oldowan behavioral variability in East Africa

Abstract

The extent, nature, and temporality of early hominin food procurement strategies has been subject to extensive debate. In this paper, we examine evidence for the seasonal scheduling of resource procurement and technological investment in the Oldowan, starting with an evaluation of the seasonal signature of USOs, freshwater resources, and terrestrial animal resources in extant primates and modern human hunter-gatherer populations. Subsequently, we use the mortality profiles, taxonomic composition, and taphonomy of the bovid assemblages at Kanjera South (Homa Peninsula, Kenya) and FLK-Zinj (Olduvai Gorge, Tanzania) to illustrate the behavioral flexibility of Oldowan hominins, who were targeting different seasonally-vulnerable demographics. In terms of the lithic assemblages, the specific opportunities and constraints afforded by dry season subsistence at FLK-Zinj may have disincentivized lithic investment, resulting in a more expedient toolkit for fast and effective carcass processing. This may have been reinforced by raw material site provisioning during a relatively prolonged seasonal occupation, reducing pressures on the reduction and curation of lithic implements. In contrast, wet season plant abundance would have offered a predictable set of high-quality resources associated with low levels of competition and reduced search times, in the context of perhaps greater seasonal mobility and consequently shorter occupations. These factors appear to have fostered technological investment to reduce resource handling costs at Kanjera South, facilitated by more consistent net returns and enhanced planning of lithic deployment throughout the landscape. We subsequently discuss the seasonality of freshwater resources in Oldowan procurement strategies, focusing on FwJj20 (Koobi Fora, Kenya). While more analytical studies with representative sample sizes are needed, we argue that inter-assemblage differences evidence the ability of Oldowan hominins to adapt to seasonal constraints and opportunities in resource exploitation.

Unravelling Hominin Activities in the Zooarchaeological Assemblage of Barranco León (Orce, Granada, Spain)

“…These communities were able to exploit a considerable range of carcass sizes in a multi-stage butchery sequence, combining access to meat with the acquisition of within-bone nutrients, such as marrow, in line with behaviours documented in the African continent during the Early Pleistocene (e.g. Bunn and Ezzo, 1993;Ferraro et al, 2013;Linares-Matás and Clark 2021), including the exploitation of large and very large animal taxa (cf. Linares-Matás and Yravedra 2022).…”

Captive bonobos (Pan paniscus) apply precision grips when using flaked stone tools

“…Our results suggest that even if animal and plant food processing behaviors were not highly efficient, it was nonetheless possible for stone tools to provide tangible benefits through the successful completion of at least some cutting actions. A meat scavenging scenario where scraps of meat are removed from carcasses (Linares‐Matás & Clark, 2022; Oliver et al, 2019), for example, would provide a context where benefits may have been realized through the application of relatively limited cutting forces. Toth et al (1993: 84) note that B1 took “from 30 [seconds] to just over 2 [minutes]” to cut through rope ~10 mm in diameter.…”

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

“…The reduction of plant availability and the evaporation of seasonal watercourses during the dry season in Africa often leads to the spatial concentration of herbivores around permanent water sources, leading to greater hunting and scavenging opportunities (Hurtado and Hill, 1990: 298;Foley, 1993;O'Connell et al, 2002;Lee, 2013;Hawkes, 2016). The dry season also represents a period of relatively high fat concentration for ungulate individuals, as fat accumulates as a result of high dietary quality in the wet season, and then subsequent depletion lags behind the reduction in dietary quality seen in the dry (Sinclair, 1975;Speth, 1987;Linares-Matás and Clark, 2021). These patterns are reflected in the greater dry season emphasis on duikers (Cephalophus spp.)…”

“…Similarly, trace-element analysis indicates Australopithecus africanus experienced seasonal dietary stress during development, resulting in recurrent periods of supplemental breastfeeding over the first few years of life (Joannes-Bayou et al, 2019). Recent research is also emphasising that seasonal fluctuations in resource availability are likely to have impacted the behavioural strategies employed by early members of the genus Homo (Hosfield, 2020;Linares-Matás and Clark, 2021).…”

“…In this paper, we propose that landscape knowledge may be one relevant additional variable that may help explain temporal changes in resource use, in both extant and extinct populations (see also Clark and Linares-Matás, 2020;Linares-Matás and Clark, 2021). We present a framework for an explicitly seasonal categorisation of resources according to their preferred or fallback nature, giving examples for each of these categories from primatological (mostly chimpanzee) and ethnographic literature.…”