How old is human longevity?

Seeking to locate changes in longevity in hominin evolution, Caspari and Lee (2004) calculated a ratio of old to young adult dentitions in assemblages of fossil taxa. They found an especially large difference in this ratio between Neandertals and Upper Paleolithic modern humans. While the important question they addressed can only be answered with fossil evidence, their ratio, as we show here, is not a measure of longevity. If their age categorizations are correct, the ratios do show very different representations of the deaths of old and young adults in the assemblages analyzed. Instead of changes in longevity, these differences more likely reflect biases in the ages at death represented in the assemblages. Caspari and Lee (2004: 10895) say: ‘‘Increased longevity, expressed as a number of individuals surviving to older adulthood, represents one of the ways the human life history pattern differs from other primates.’’ Using an analysis of tooth wear to classify fossil dentitions as young or old adults, they concluded that the longevity characteristic of modern humans first appeared in the late Pleistocene and contributed significantly to