Computer simulation of scavenging by hominins and giant hyenas in the late Early Pleistocene

Abstract

Consumption of animal-sourced food is an important factor in broadening the diet of early hominins, promoting brain and body growth, and increasing behavioural complexity. However, whether early hominins obtained animal food by scavenging or hunting large mammals remains debated. Sabre-toothed felids have been proposed to facilitate the expansion of early Homo out of Africa into Europe 1.4-0.8 Ma by creating a niche for scavengers in Eurasia as the carcasses abandoned by these felids still contained abundant edible resources. In contrast, it has been argued that the niche for a large scavenger was already occupied in Eurasia by the giant hyena, preventing hominins from utilising this resource. This study shows that sabre-toothed felids generated carcasses rich in edible resources and that hominins were capable of competing with giant hyenas for this resource. The simulation experiments showed that maintaining an optimum group size is essential for the success of the hominin scavenging strategy. Early hominins could outcompete giant hyenas only if they could successfully dispute carcasses with them. Thus, in the presence of a strong competitor, passive scavenging is essentially the same as confrontational scavenging.

Figure 1

Final number of scavengers in the experiments. Hominins are represented in red (continuous line) and hyenas in green (dashed line). Three experiments were performed by varying the densities of predators for Scenario 1 (a, c, e) and Scenario 2 (b, d, f) from low density (a, b) to medium density (c, d) to high density (e, f). The limits of the boxes correspond to the first and third quartiles; the median is presented with a horizontal line. The whiskers mark the maximum and minimum without outliers or extreme values. Outliers and extreme values are indicated with a white dot and an asterisk, respectively.

Figure 2

Energy expenditure of scavengers. The results of the experiments are shown in relation to the size of the hominin groups. Three experiments were performed for each scenario by varying the densities of predators from low density (red line) to medium density (blue line) to high density (green line). The limits of the boxes correspond to the first and third quartiles; the median is shown by a horizontal line. The whiskers mark the maximum and minimum without outliers and extreme values. Outliers and extreme values are indicated with a white dot and an asterisk, respectively.