Grandmothers and the evolution of human longevity
Version of Record online: 14 APR 2003
Copyright © 2003 Wiley-Liss, Inc.
American Journal of Human Biology
Volume 15, Issue 3, pages 380–400, May/June 2003
How to Cite
Hawkes, K. (2003), Grandmothers and the evolution of human longevity. Am. J. Hum. Biol., 15: 380–400. doi: 10.1002/ajhb.10156
- Issue online: 14 APR 2003
- Version of Record online: 14 APR 2003
- Manuscript Accepted: 9 DEC 2002
- Manuscript Received: 16 AUG 2002
Great apes, our closest living relatives, live longer and mature later than most other mammals and modern humans are even later-maturing and potentially longer-lived. Evolutionary life-history theory seeks to explain cross-species differences in these variables and the covariation between them. That provides the foundation for a hypothesis that a novel role for grandmothers underlies the shift from an ape-like ancestral pattern to one more like our own in the first widely successful members of genus Homo. This hypothesis links four distinctive features of human life histories: 1) our potential longevity, 2) our late maturity, 3) our midlife menopause, and 4) our early weaning with next offspring produced before the previous infant can feed itself. I discuss the problem, then, using modern humans and chimpanzees to represent, respectively, genus Homo and australopithecines, I focus on two corollaries of this grandmother hypothesis: 1) that ancestral age-specific fertility declines persisted in our genus, while 2) senescence in other aspects of physiological performance slowed down. The data are scanty but they illustrate similarities in age-specific fertility decline and differences in somatic durability that are consistent with the hypothesis that increased longevity in our genus is a legacy of the “reproductive” role of ancestral grandmothers. Am. J. Hum. Biol. 15:380–400, 2003. © 2003 Wiley-Liss, Inc.