Our proto-human ancestors, Homo erectus, preferred a high-fat diet and hunted Middle-Eastern elephants (Elephas antiquus) to extinction 400,000 years ago, at which point Homo erectus more or less disappeared, and more gracile proto-humans took over:
It is our contention that two distinct elements combined in the Levant to propel the evolutionary process of replacing H. erectus by a new hominin lineage.
As the classification of varieties of the genus Homo is problematic, we refrain in this paper from any taxonomic designations that would indicate species or subspecies affiliation for the hominins of Qesem Cave. The Qesem Cave hominin, based on the analysis of teeth shares dental characteristics with the Skhul/Qafzeh Middle Paleolithic populations and to some extent also with Neandertals).
One was the disappearance of the elephant (Elephas antiquus) – an ideal food-package in terms of fat and protein content throughout the year – which was until then a main calorie contributor to the diet of the H. erectus in the Levant.
The second was the continuous necessity of H. erectus to consume animal fat as part of their diet, especially when taking into account their large brains. The need to consume animal fat is the result of the physiological ceiling on the consumption of protein and plant foods. The obligatory nature of animal fat consumption turned the alleged large prey preference of H. erectus into a large prey dependence.
Daily energy expenditure (DEE) of the hominins would have increased when very large animals such as the elephant had diminished and a larger number of smaller, faster animals had to be captured to provide the same amount of calories and required fat. This fitness pressure would have been considerably more acute during the dry seasons that prevail in the Levant.
Such an eventuality, we suggest, led to the evolution of a better equipped species, in comparison with H. erectus, that also had a lighter body, a greater lower limb to weight ratio, and improved levels of knowledge, skill, and coordination allowing it to better handle the hunting of an increased number of smaller animals and most probably also develop a new supporting social organization.
(Hat tip to David Foster.)
I had the opportunity to hear UM Professor John Speth discuss big game hunting by modern-day hunter gatherer societies like the Kalahari Bushmen; he contradicts the idea that humans engaged in big game hunting by necessity in a cool paper available online:
Speth is also mentioned (disparagingly) in the fascinating paper referenced in this post, which offers a lot of speculation built on good science data about nutrition and the human gut, in addition to the archaeogical finds.