The study's most intriguing data may be those gleaned from the tooth of a Neandertal infant. The results suggest that the infant was exclusively breastfed for a little over 7 months, and then the mother’s milk was supplemented with other food for another 7 months. After that, barium levels dropped rapidly, suggesting a sudden end to breastfeeding.
Arora says that 14 months is relatively early to wean a child: humans in non-industrial societies stop breastfeeding at an average age of about 2.5 years.
The team's results were based on a single sample of Neandertal tooth, which makes it difficult to draw broad conclusions. Perhaps Neandertals typically weaned their young more quickly than humans, suggesting that they may have had children at shorter intervals, says Louise Humphrey, an anthropologist at the Natural History Museum in London. But she says it is also possible that the abrupt end to breastfeeding indicates that the infant’s mother may have fallen ill or died.