Other than the clerk at the drive-through window, our acquisition of meat for our diet generally involves two creatures – the one eating and the one the meat came from. A new study points out that, for most of our existence, there was a third – scavengers like vultures, hyenas and lions. The evolution of humans depended on these creatures and the possible extinction of them will have serious consequences on our own survival as a species.

Researchers Marcos Moleón and José Antonio Sánchez Zapata of the University Miguel Hernández in Elche, Spain, traced the evolution of humans in relation to the various ways they got their meat. They point out in their study, reported in the journal BioScience, that at every stage, the key component was the humanoids’ relationship with scavengers.

The way that humans have acquired meat since it became a fundamental component of our diet has changed from the consumption of dead animals to hunting live ones, the domestication of wild animals and finally intensive exploitation. In each of these periods, humans have been closely related to other scavengers. At first, the interaction was primarily competitive, but when humans went from eating carrion to generating it, scavengers highly benefitted from the relationship. Today humans benefit the most from the multiple services provided by scavengers.

Hyenas stealing food from a lion

Besides leading us to dead meat, the scavengers helped control infectious diseases by eating rotting wastes. They also stimulated diversity and invention by forcing early humans to create stone tools and weapons in order to compete with them for food. The report describes the importance of this:

… the two most distinctive human attributes, language development and cooperative partnership, were probably the result of selective pressures associated with consumption of carrion.

Unfortunately, vultures and large carnivorous mammals are threatened and approaching extinction in many parts of the world. The study warns that the loss of these species will be devastating to humans and our ecosystem. Will we be able to carry on when we no longer have help with carrion?

Will it come to this?