Menopause in Free-Ranging Rhesus Macaques: Estimated Incidence, Relation to Body Condition, and Adaptive Significance
Source: International Journal of Primatology, Volume 19, Number 4, August 1998 , pp. 751-765(15)
Abstract:We examined the question of whether the occurrence of menopause in rhesus macaque (Macaca mulatta) females approximates that found in women from a life history standpoint. We used data from two provisioned free-ranging populations of rhesus macaques to estimate the probability that a juvenile female not only will survive to the potentially postmenopausal age of 25 years but also will cease to experience menstrual cycles between 25 and 27 years. We used the same data to assess whether an age-related deterioration in body condition can predict whether females ≥25 years old will be acyclic. Our analyses indicate that, within our study populations, (1) ≤1 in every 10 juvenile females can be expected eventually to undergo the climacteric, and (2) being in poor condition is strongly associated with being acyclic in old age. Current theory regarding the evolution of senescence in species that do not reproduce by binary fission posits that aging is a consequence of the force of natural selection declining with age. Inasmuch as the proportion of female rhesus macaque juveniles that ultimately experience menopause is small, and inasmuch as reproductive senescence does not appear to outpace organismal aging in general (as indexed by an age-related decline in body condition), we conclude that the occurrence of menopause in rhesus females is parsimoniously explained by the general evolutionary theory of aging and that the invocation of a special adaptive explanation, such as the grandmother hypothesis or a variant thereof, is unnecessary.
Document Type: Research Article
Affiliations: 1: Charles River—Key Lois, 24244 U.S. 1, Summerland Key, Florida 33042. RodJohn@juno.com 2: Charles River—Key Lois, 24244 U.S. 1, Summerland Key, Florida 33042. Division of Veterinary Resources, University of Miami School of Medicine, 12500 S. W. 152nd Street, Miami, Florida 33177
Publication date: August 1, 1998