In a latest survey, it has been said that non-human primates don't have immunity to the fading female fertility that comes with age, however human females have no such problems.
Co-author Susan Alberts of Duke University and the National Evolutionary Synthesis Center, said that unlike other primates, women tend to have a long post-reproductive life.
According to her, even before modern medicine, many women lived for 30 to 35 years after their last child was born.
The study was concluded after Alberts and colleagues compared mortality and fertility data for seven species of wild primates to similar data for the! Kung people of Southern Africa, a human population of hunter-gatherers with limited access to modern medicine or birth control.
The nonhuman primate data were based on long-term observations of 700 adult females, including capuchins in Costa Rica, muriqui monkeys in Brazil, baboons and blue monkeys in Kenya, chimpanzees in Tanzania, gorillas in Rwanda and sifakas in Madagascar.
The researcher estimated that for each species, the pace of reproductive decline - measured as the probability, at each age, that a female's childbirth will be her last - and compared it with the rate of decline in overall health, measured as the odds of dying with each passing birthday.
According to Albert, in this way they were able to compare the rate of aging in the reproductive system with the rate of aging in the rest of the body.
The results suggest that in nonhuman primates, reproductive decline is surpassed by declines in survival, so that very few females run out of reproductive steam before they die.
Alberts said that 50 percent of women experience menopause by the age of 50, and fertility starts to decline about two decades before that.In both humans and chimpanzees, for example, female fertility starts to decline in the late 30s and early 40s.
She further added that in human populations with little access to modern medicine, like the !Kung hunter-gatherers in this study, most women survive for decades after their last child is born. Nonhuman primates rarely do that.
It further shows that if evolution has given us longer lifespans than our primate cousins, why hasn't female reproduction kept pace? And in a world where individuals with more offspring tend to win the evolutionary contest, why shut down reproduction with decades of survival still ahead?
It may be that older females who forego future breeding to invest in the survival of their existing children and grandchildren gain a greater evolutionary edge than those who continue to reproduce. Once a baby chimp is weaned it can forage for itself, whereas human infants are nutritionally dependent long after they leave the breast.
(With inputs from ANI)
Here are the interview taken from Dr. Alka Varshney, Gynaecologist on the problem related to Menopause and its impact on women. The interview highlights various facts about the Menopause and its effect including the way by which women can minimise and overcome the impact of Menopause for them.
|
|
Comments:
