If we go back two or three million years in time, and travel to South Africa, we will meet one of our ancestors, Australopithecus africanus , a creature halfway between man and monkey. How could we, today, know what those distant relatives of ours ate?
Using pioneering high-tech methods, researchers from New York’s Mount Sinai Hospital, working as part of an international team, have analyzed the composition of five fossilized teeth found in Sterkfontein Cave – outside Johannesburg (South Africa) – and have discovered never-before-known breastfeeding patterns in an early human species, according to the study published in the July issue of the journal Nature .
The growth patterns of the teeth, which resemble tree rings, allow researchers to determine the concentrations of barium – an element found in milk – in the teeth over time, providing information about breastfeeding and feeding.
Breastfeeding, feeding and parenting
Breastfeeding is a critical aspect of human development, and the duration of exclusive breastfeeding and the timing of introduction of solid foods into the diet are also important health factors in human and other primate populations. Many aspects of parenting, however, remain poorly understood. Researchers have found that this species was exclusively breastfed for a year, but continued to suckle from time to time afterward, especially during periods of food shortage.
More humans than apes
“Our results show that this species is a little closer to humans than the other great apes, who have such different breeding behaviors,” says one of the researchers in the study, Dr. Christine Austin, associate professor of Environmental Medicine and Health. Public at the Icahn School of Medicine on Mount Sinai and a member of its Institute for Exposomic Research.
“These findings are important from an evolutionary perspective, because humans have long infancy and short lactation periods, while monkeys have longer lactation periods than humans, ” Austin continues. We are still in the dark as to why or when we made that change and what is the effect that the recent important changes in breastfeeding, with agriculture and industrialization, could have on the health of mothers and babies ” .
The Institute for Exposure Research at Mount Sinai Hospital is investigating how to develop exposure biomarkers, one of which is to measure chemicals in teeth. According to Dr. Austin, diet is an important part of the exposome – a person’s history of environmental exposure – and it is important to measure nutritional stress to understand overall health after exposures.
“For the first time, we have gained a new perspective on how our ancestors raised their offspring, and how mothers may have adapted to seasonal food shortages with breastfeeding,” said the study’s lead author, Dr. Renaud Joannes-Boyau, director of the Research Group in Geoarcheology and Archaeometry (GARG) at Southern Cross University in Australia.
Image: A mother and a calf of the Australopithecus africanus species. Illustration by José García and Renaud Joannes-Boyau.
