Missing Mothers: Within and Between Generation Effects of Maternal Loss in Primates
Dr. Matthew Zipple
The dependent relationship between mother and offspring is a defining characteristic of mammalian life history. In primates and other long-lived mammals, the importance of this relationship does not end when offspring become nutritionally independent. Rather, mothers continue to provide important knowledge and social resources well into the juvenile period, and occasionally into adulthood. In this talk, I will explore the negative consequences that primate offspring face when this most important social relationship is severed in early life due to maternal death. I'll describe my work in baboons and other primates that reveals two surprising results. First, offspring are more likely to die during the years preceding their mothers' deaths-- a period when those mothers are still alive but will die in the near future. Strikingly, this effect is not restricted only to the weeks or months preceding maternal death, but rather extends for several years prior to maternal death. And second, offspring that lose their mothers in early life appear to face lifelong negative consequences, which they in turn pass onto their own offspring, representing the best evidence to date of intergenerational transmission of early adversity in wild long-lived animals. These results have important implications for the evolution of the long, slow lives that characterize many primates and some other highly social mammals. I'll close by discussing unpublished work in which I consider the implications of severing the mother-offspring relationship via the death of the child, rather than the death of the mother. Building on sociological and medical literature, I'll present a model of how human maternal mortality has declined and maternal lifespan increased in the past century as a result of the massive reduction in child mortality that characterized the 20th century.