Life history context of reproductive aging in a wild primate model

Abstract

The pace of reproductive aging has been of considerable interest, especially in regard to the long postreproductive period in modern women. Here we use data for both sexes from a 37-year longitudinal study of a wild baboon population to place reproductive aging within a life history context for this species, a primate relative of humans that evolved in the same savannah habitat as humans did. We examine the patterns and pace of reproductive aging, including birth rates and reproductive hormones for both sexes, and compare reproductive aging to age-related changes in several other traits. Reproductive senescence occurs later in baboon females than males. Delayed senescence in females relative to males is also found in several other traits, such as dominance status and body condition, but not in molar wear or glucocorticoid profiles. Survival, health, and well-being are the product of risk factors in morphological, physiological, and behavioral traits that differ in rate of senescence and in dependence on social or ecological conditions; some will be very sensitive to differences in circumstances and others less so.

Senescence or selective disappearance? Age trajectories of body mass in wild and captive populations of a small-bodied primate

“…[16,19,20]). In the wild, studies of FS have largely focused on long-lived, large-bodied animals that face relatively low levels of environmental hazard (ungulates [10,21], sea-birds [22], seals [23] and primates [6,24]). Because FS is more detectable when EM is low, this taxonomic bias may lead to an overestimation of the prevalence of FS compared with the influences of selective disappearance in natural populations across species.…”

Social status predicts wound healing in wild baboons

“…For instance, in baboons, dominance rank declines with age (40), and senescence alone might lead to poor immune function in lowranking males (50). Body mass index also declines with age (43), and this effect, combined with the fact that low-ranking males are more likely than high-ranking males to be interrupted while feeding (51), might limit the energy low-ranking males can devote to immune function. Finally, glucocorticoid levels are higher in low-ranking males than in high-ranking males (other than the alpha male) (42,45).…”

“…Male baboons are a good system for understanding the relationships between dominance rank and immune function because high male rank usually leads to high reproductive success (40,41) and because we already know a good deal about the behavioral and physiological correlates of dominance rank in baboons (41)(42)(43)(44)(45). Baboons live in multimale, multifemale social groups characterized by linear dominance hierarchies.…”

Primate aging in the mammalian scheme: the puzzle of extreme variation in brain aging

“…Chimpanzee menopause is about the same age as in humans in captivity and in the wild (Atsalis and Videan 2009;Finch and Holmes 2010;Hawkes and Smith 2010). Female baboons show significant reproductive decline at 18 years of age and undergo menopause in their early 20s in a feral population where adult life expectancy is only 12 years (Altmann et al 2010;Bronikowski et al 2002). Ironically, reproductive senescence in these baboons occurs much earlier in males, although it is mediated by male-male dominance interactions and represents reduced access to females rather than reduced male fertility (Altmann et al 2010).…”

“…Female baboons show significant reproductive decline at 18 years of age and undergo menopause in their early 20s in a feral population where adult life expectancy is only 12 years (Altmann et al 2010;Bronikowski et al 2002). Ironically, reproductive senescence in these baboons occurs much earlier in males, although it is mediated by male-male dominance interactions and represents reduced access to females rather than reduced male fertility (Altmann et al 2010). The importance of studying animals in nature to understand life history evolution becomes evident when considering that female reproductive senescence may occur earlier in captive populations than in the wild, possibly due to accelerated maturation combined with captive breeding practices (Atsalis and Videan 2009).…”