The last three million years have been characterised by strong climatic instability that drove many species to extinction. Australopithecus africanus lived in highly seasonal environments mostly dominated by open grasslands and wooded habitats. We have reconstructed the early life of this hominin species through an innovative approach based on tooth biogeochemistry that allows us to accurately measure dietary, physiological and behavioural responses to seasonal fluctuations in food availability. Our results suggest that A. africanus were cyclically breastfeeding their babies for their first 4 to 5 years of their life, similar to what we see today in great apes. The extended breastfeeding probably led to prolonged interbirth intervals, and ultimately may have had a negative effect on the reproductive rate of this species.

Associate Professor Luca Fiorenza is the head of the Palaeodiet Research Lab in in the Department of Anatomy and Developmental Biology at Monash University, Australia. His research focuses on functional morphology of the masticatory apparatus in human and non- human primates, and on the importance of the role of diet in human evolution. He has published peer-reviewed articles in top science journals such as Nature and Nature, Ecology & Evolution, and he has been listed among the Australia's Top Researchers by The Australian's Research 2020 Magazine as Leader in the field of Anthropology.