Life story in a tooth

Most child health experts agree that a minimum of six months of breastfeeding is essential for the welfare of growing babies, although how well such recommendations are carried out widely varies across the globe. Less is known about the breastfeeding habits of other primates — and much less still about those of prehistoric humans. A research team now reports a new technique for accurately detecting when babies were weaned, using chemical signatures in their teeth. The method was successfully applied to the tooth of a Neanderthal child, raising the possibility that researchers could decipher the life histories of our evolutionary cousins and even gain insights into why they went extinct.

Fossils of prehistoric humans and other primates are relatively rare because bone does not last well in most environments. Teeth, on the other hand, are hard and strong enough to survive through the ages, and they are often found at palaeontological and archaeological sites. Researchers have worked diligently to extract information from ancient teeth. Palaeontologists recently reported finding the teeth of the earliest apes, and archaeologists have used chemical isotopes in the teeth of early farmers to track their movements across the landscape.

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