What doesn’t kill you makes you stronger. Or so the saying goes. For female baboons, that may not be quite true.
A new study published in Nature Communications this month has found that the cumulative effects of traumatic events during early life in female baboons can substantially shorten their lifespans. Female who experience three or more sources of adversity during their early life can live ten years fewer than a female who experiences a comparatively untroubled existence
Wild animal populations are subjected to many sources of environmental stress during their lifetimes, and those experienced during early life (the period between conception and reproductive maturity) were the focus of a team led by Jenny Tung of Duke University. Tung and colleagues used data on the baboon population of Amboseli in southern Kenya to examine the effects of six sources of adversity during the early life of female baboons. This population has been continuously monitored since 1971 by the Amboseli Baboon Research Project, so the researchers were able to examine the effects of droughts, population size, mothers’ social rank and social relationships, loss of a mother, and the presence of competing younger siblings on the lives of 196 female baboons.
The cumulative model used in this study predicts that female baboons which experience one or none of these stressful events will have a median lifespan of 18 to 24 years. In stark contrast, a female baboon that experiences three or more of these events will likely die by the age of 9 years. Like other non-human primates, female baboons are capable of producing young throughout most of their adult lives, and don’t often live beyond their reproductive years. Females with shorter life spans will of course produce fewer offspring during their lifetimes, which in turn can affect population sizes and the overall fitness of the species.
Childhood trauma is known to negatively affect adult health and longevity in both animals and humans. This is thought to be partly caused by poor social environments which persist into adult life and reduce adult health and survival. Previous studies on the Amboseli baboon population have shown that social isolation during adulthood predicts shorter lifespans in females, and now it seems that this social isolation during adulthood can be predicted by traumatic events in early life.
Interestingly, this only seems to be the case with relationships between adult female baboons – social relationships between females and males do not appear to be affected by the early life experiences of females. So, while female relationships suffer, traumatised female baboons may find some solace in social relationships with male baboons.
Tung, J., Archie, E. A., Altmann, J., & Alberts, S. C. (2016). Cumulative early life adversity predicts longevity in wild baboons. Nat Commun, 7. dx.doi.org/10.1038/ncomms11181
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