Paper short abstract:

To investigate human kinship we need some idea of how the species that evolved into us might have organised themselves. How Homo erectus females provisioned their offspring would have been a major determinant of their social system. I test two theories of provisioning and suggest an alternative.

Paper long abstract:

Homo erectus was the first undisputed member of our genus. They evolved in Africa 1.9 million years ago with increased brain-size, and a body shape and size similar to modern humans. It is clear that Homo erectus were a hugely successful species: lasting more than I million years, developing a new and sophisticated stone-tool technology and colonising much of the old world. What is remarkable is that we know so little about the way these hominids, that ultimately evolved into modern humans, organised themselves.

Continued support for the 1960s 'Man the hunter' ideas comes from current research proposing that Homo erectus males hunted savannah herbivores providing meat to females and their offspring in return for paternity certainly and monogamy. Others argue that older females, as their fertility declined, provided for their daughters' offspring by digging tubers, leading to matrilineal groups. Both positions are based on data from modern hunter-gatherer populations.

I have evaluated these theories by modelling the energetic requirements of Homo erectus females and their offspring using data from chimpanzees and modern hunter-gatherers. The results question the possibility of either males or 'grandmothers' being able to support reproductive females on their own and suggest that both would have been necessary. This would have amounted to a revolution in social system and has major implications for the origin of modern human kinship.