Secondly, Stanford presents evidence that hunting and scavenging was a strategy used when needed to support a lack of vegetation. Data showing increased hunting activity during dry seasons and droughts supports this position. However, there is also reason to believe that hunting and scavenging was an important part of hominid sustenance that provided nutrients and influenced hominid behavioral ecology and sociobiology. This is the third option Stanford explores. He explains that hunting success has been found to increase with size of hunting party, implying that hunting is a social activity.
Most likely females choose mates based on their hunting ability.
Chimpanzee predation has also played a role in shaping the ecology. It has been shown that chimpanzee predation upon red colobus monkeys has influenced colobus group size and structure. Therefore, there is merit to the idea that hunting and scavenging were principal components in hominid evolutionary ecology. Stanford closes by mentioning the possibility that hunting and scavenging became of greater importance over time and therefore each of the previously discussed scenarios may have been true at one time during human evolutionary history. He suggests the first option makes sense within the australopithecine radiation, while the third category is better applied to later stages of human evolution.