But a new study puts at least some of the blame on bunnies. Or, to be more specific, on Neanderthals' apparent inability to exploit the "high-biomass prey resource" of rabbits when prehistoric deer and other large prey mammals became scarce on the Iberian Peninsula.
Dr. John Fa of Britain's Durrell Wildlife Conservation Trust presented the theory in a study titled "Rabbits and Hominin Survival in Iberia," which was published online on Feb. 17 in the Journal of Human Evolution.
"We suggest that hunters that could shift focus to rabbits and other smaller residual fauna, once larger-bodied species decreased in numbers, would have been able to persist," Fa and his collaborators write of their research.
For the study, Fa and his team visited excavation sites in Portugal, Spain and southern France, and counted the number of animal skeletons found in each, New Scientist reported.
Based on the skeleton tallies, the researchers concluded that deer and other large animals were plentiful until 30,000 years ago. Fa found that rabbit skeletons were plentiful in later periods, when modern humans were the only hominids left. Fa said that while Neanderthals would have eaten other things besides meat, their inability to take advantage of the rabbits as a primary nutrient source might have been "another 'nail in the coffin'" for the species.
"Our point is that Neanderthals, for some reason, may have not been able to turn to smaller prey once the larger species disappeared," Fa told the Huffington Post in an email. "This pattern of hunters progressively using smaller prey once larger ones have been depleted is typical of hunter-gatherers throughout the world."
Why might modern humans be better than Neanderthals at hunting rabbits? Fa told the HuffPost that modern humans might have developed a "more elaborate system of cooperation" in their early societies. "Maybe women and children dedicated themselves to rabbit hunting, and men to hunting the larger prey," Fa wrote.
Fa's next project will continue his work studying rabbit meat and its importance as a food source exploited by both Neanderthals and modern humans, as seen in the chemical content of hunters' bones.
"Although some more fine-tuning needs to be done to be able to detect rabbit, we would like to demonstrate that in Neanderthals the main prey items are large animals, but not so in [modern humans]," Fa wrote. "These results would indeed confirm what we are saying –- an abundant source of meat was neglected by Neanderthals."