MONASH UNIVERSITY
Extended parental care is considered one of the hallmarks of human evolution. A stunning new research result published today in Nature reveals for the first time the parenting habits of one of our earliest extinct ancestors.
Analysis of more than two-million-year-old teeth from Australopithecus africanus fossils found in South Africa have revealed that infants were breastfed continuously from birth to about one year of age. Nursing appears to continue in a cyclical pattern in the early years for infants; seasonal changes and food shortages caused the mother to supplement gathered foods with breastmilk. An international research team led by Dr. Renaud Joannes-Boyau of Southern Cross University, and by Dr. Luca Fiorenza and Dr. Justin W. Adams from Monash University, published the details of their research into the species in Nature today.
“For the first time, we gained new insight into the way our ancestors raised their young, and how mothers had to supplement solid food intake with breastmilk when resources were scarce,” said geochemist Dr. Joannes-Boyau from the Geoarchaeology and Archaeometry Research Group (GARG) at Southern Cross University.
“These finds suggest for the first time the existence of a long-lasting mother-infant bond in Australopithecus. This makes us to rethink on the social organisations among our earliest ancestors,” said Dr. Fiorenza, who is an expert in the evolution of human diet at the Monash Biomedicine Discovery Institute (BDI).
“Fundamentally, our discovery of a reliance by Australopithecus africanus mothers to provide nutritional supplementation for their offspring and use of fallback resources highlights the survival challenges that populations of early human ancestors faced in the past environments of South Africa,” said Dr. Adams, an expert in hominin palaeoecology and South African sites at the Monash BDI.
For decades there has been speculation about how early ancestors raised their offspring. With this study, the research team has opened a new window into our enigmatic evolutionary history.
Australopithecus africanus lived from about two to three million years ago during a period of major climatic and ecological change in South Africa, and the species was characterised by a combination of human-like and retained ape-like traits. While the first fossils of Australopithecus were found almost a century ago, scientists have only now been able to unlock the secrets of how they raised their young, using specialised laser sampling techniques to vaporise microscopic portions on the surface of the tooth. The gas containing the sample is then analysed for chemical signatures with a mass spectrometer- enabling researchers to develop microscopic geochemical maps which can tell the story of the diet and health of an individual over time. Dr. Joannes-Boyau conducted the analyses at the Geoarchaeology and Archaeometry Research Group at Southern Cross University in Lismore NSW and at the Icahn School of Medicine at Mount Sinai in New York.
PhysOrg for more