Hunting hypothesis

Killing wildlife in human evolution
the 1976 book
In paleoanthropology, the hunting hypothesis is the hypothesis that human evolution was primarily influenced by the activity of hunting for relatively large and fast animals, and that the activity of hunting distinguished human ancestors from other hominins. While it is undisputed that early humans were hunters, the importance of this fact for the final steps in the emergence of the genus Homo out of earlier australopithecines, with its bipedalism and production of stone tools (from about 2.5 million years ago), and eventually also control of fire (from about 1.5 million years ago), is emphasized in the "hunting hypothesis", and de emphasized in scenarios that stress the omnivore status of humans as their recipe for success, and social interaction, including mating behaviour as essential in the emergence of language and culture. Advocates of the hunting hypothesis tend to believe that tool use and toolmaking essential to effective hunting were an extremely important part of human evolution, and trace the origin of language and religion to a hunting context. As societal evidence David Buss cites that modern tribal population deploy hunting as their primary way of acquiring food. The Aka pygmies in the Central African Republic spend 56% of their quest for nourishment hunting, 27% gathering, and 17% processing food. Additionally, the !Kung in Botswana retain 40% of their calories from hunting and this percentage varies from 20% to 90% depending on the season. For physical evidence Buss first looks to the guts of humans and apes. The human gut consists mainly of the small intestines, which are responsible for the rapid breakdown of proteins and absorption of nutrients. The ape's gut is primarily colon, which indicates a vegetarian diet. This structural difference supports the hunting hypothesis in being an evolutionary branching point between modern humans and modern primates. Buss also cites human teeth in that fossilized human teeth have a thin enamel coating with very little heavy wear and tear that would result from a plant diet. The absence of thick enamel also indicates that historically humans have maintained a meat heavy diet. Another possible explanation for women gathering is their inherent prioritization of rearing offspring, which is difficult to uphold if women were hunting. Hunting is seen as more cost effective for men than for women. The division of labor allows both types of resources (animals and plants) to be utilized. Since women hunt while menstruating, and if a child is still being breastfed, the mother may take him or her along in a shoulder sling while hunting or gathering. These reproductive benefits lead to greater reproductive success in more skilled hunters. Provisioning may actually be a form of sexual competition between males for females. Hawkes suggests that male provisioning is a particularly human behavior, which forges the nuclear family. The structure of familial provisioning determines a form of resource distribution. However, Hawkes does acknowledge inconsistencies across societies and contexts such as the fluctuating time courses dedicated to hunting and gathering, which are not directly correlated with return rates, the fact that nutrition value is often chosen over caloric count, and the fact that meat is a more widely spread resource than other resources.

The show off hypothesis is the concept that more successful men have better mate options. The idea relates back to the fact that meat, the result of hunting expeditions, is a distinct resource in that it comes in large quantities that more often than not the hunter's own family is not able to consume in a timely manner so that the meat doesn't go sour. Also the success of hunting is unpredictable whereas berries and fruits, unless there is a drought or a bad bush, are fairly consistent in seasonality. Kristen Hawkes argues that women favor neighbors opting for men who provide the advantageous, yet infrequent meat feasts. These women may profit from alliance and the resulting feasts, especially in times of shortage. Hawkes suggests that it would be beneficial for women to reward men who employ the “show off strategy” by supporting them in a dispute, caring for their offspring, or providing sexual favors. The benefits women may gain from their alignment lie in favored treatment of the offspring spawned by the show off from neighbors. Buss echoes and cites Hawke's thoughts on the show off's benefits in sexual access, increased likelihood of having children, and the favorable treatment his children would receive from the other members of the society. Hawkes also suggests that show offs are more likely to live in large groups and thus be less susceptible to predators. Show offs gain more benefits from just sharing with their family (classical fitness) in the potential favorable treatment from the community and reciprocal altruism from other members of the community. Hawkes uses the Ache people of Paraguay as evidence for the Show off hypothesis. Food acquired by men was more widely distributed across the community and inconsistent resources that came in large quantities when acquired were also more widely shared. While this is represented in the Ache according to Hawkes, Buss notes that this trend is contradicted in the Hadza who evenly distribute the meat across all members of their population and whose hunters have very little control over the distribution. In the Hadza the show off hypothesis does not have to do with the resources that result from hunting, but from the prestige and risk that is involved in big game hunting. There are possible circuitous benefits such as protection and defense.

The Gathering Hypothesis is the view that men provided critical evolutionary propulsion of the modern human through hunting, whereas women contributed via gathering. In addition, it helps provide for the fact that our ancestor's diets consisted mostly of plant food. It's suggested by David Buss that stone tools were invented not strictly for hunting, but for gathering plants and used for digging them up. This could explain the migration from forests to woodlands as tools allowed easy access to previously used methods. As such, this view results in the hunting part of the modern human coming much later. Though women weren't strictly hunters, a woman's time investment in foraging depended on how much food her husband brought back. Gathering plant foods allows a person to return to camp when necessary, but hunting may require an overnight stay so as to continue tracking the animal in the morning.

The Gathering Hypothesis has been criticized by those who believe it's incapable of explaining our human origins in the primate lineage. A common argument against the Gathering hypothesis is if gathering was the best or most efficient method of acquiring food, then why wouldn’t men just gather and stop wasting their time hunting. The division of labor among men and woman is unaccounted for throughout cultures. Hunting often takes the hunter far away from the home base, selection would favor hunters who could find their way home without getting lost along the way. Locating and gathering edible nuts, berries, fruit, and tubers would require a different set of spatial skills. The high prevalence of male hunters and female gatherers among traditional societies, although not conclusive evidence, provides one more clue that both activities are part of the human pattern of procuring food.