It’s only one case.  One tooth from a Neanderthal infant.  One tooth that provides a suggestive piece of evidence for when that infant may have transitioned from mother’s milk to solid food some 100,000 years ago. But the foundation of science built around this one case, as explored in coverage by Adam Cole at NPR, John Noble Wilford at the New York Times, and others,  make it an impressive example of how scientists attempt to reconstruct biology and behavior in the distant past, and come away with some degree of confidence in their effort.  The research reported in Nature was not in fact focused on the Neanderthal tooth, but instead on documenting how weaning from breastmilk in modern human and macaque infants affects, and can be documented in, tooth development.  However, these studies served as critical positive controls for the Neanderthal analysis, essentially validations for using the same techniques in studying a fossil tooth.  To wit, the element barium is reliably transferred in breast milk from primate mothers to their infants, and can be detected with substantial precision in layers of tooth enamel, with an inherent time stamp, producing similar patterns detectable in the infant teeth of humans, macaques, and now a Neanderthal, which indicate when weaning off breast milk occurs in each case.  Sure, the news reports probably put too much emphasis on the Neanderthal part of the research.  One case certainly does not prove that Neanderthal infants stop breast feeding at about 14 months.  On the other hand, there is good reason to expect that this finding will be affirmed as additional cases are studied, with the interesting possibility that Neanderthals were not obviously different from their primate cousins.