Australasian Science: Australia's authority on science since 1938

Neanderthals Weaned Early

By Stephen Luntz

A study of a Neanderthal tooth has revealed that the child it belonged to was exclusively breastfed for 7 months, followed by supplementation with other foods for another 7 months before weaning.

A team from four Australian and two American universities showed that, in both humans and macaque monkeys with a known nursing history, tooth enamel can be used to accurately determine the age of weaning.

Barium builds up in our bones and is mobilised along with calcium when mothers start to breastfeed. As a result, breast milk is higher in barium than other foods. Teeth lay down daily layers of enamel, like tree rings, which can be examined to reveal barium levels in the diet. The less breast milk, the lower the barium.

A Neanderthal tooth from Belgium has been “well preserved,” says Dr Manish Arora of the University of Sydney. “It has already been sectioned, and we know a little about this individual,” who appears to have died at the age of eight.

However, while Arora says the evidence is clear for the age at which breastfeeding ceased, he cautions that a much larger sample size is required to know whether Neanderthals generally stopped breastfeeding at 14 months, which is much earlier than the typical 30 months of pre-industrial societies.

“Other specimens are in museums all over the world, so to compare Neanderthals and other extinct species of humans we will need many groups to work together,” Arora says.

The work was published in Nature, and accompanied by an article arguing that the early weaning is a sign of collective raising of children. However, Arora says this commentary was supplied by someone not involved in the research itself, and he is reluctant to speculate.

“There are many theories out there as to whether longer or shorter periods of breastfeeding would benefit survival. If you wean more quickly you can reproduce faster, but one tooth does not demonstrate what was typical,” Arora says.