Menopause has never before been observed in monkey species. Menopause had only previously been diagnosed in humans and in a number of toothed whale species.
The study shows that menopause occurs under certain conditions. These circumstances differ from those of humans: for example, there is no help from ancestors. While our grandfathers and grandmothers often help raise the children, older female chimpanzees usually do not get close to their young daughters and children.
The study studied the Ngogo community in western Uganda in Kibale National Park for decades. Scientists took many urine and hormone samples to check menopause and the length of life after the fertile period. Menopause in chimpanzees begins around the age of fifty. As in humans, fertility declines from age 30.
Ngogo chimpanzees live longer after they are fertile. This has also been previously observed in captive monkeys. According to researchers, the reason for the longer lifespan may be the abundance of food and the lack of enemies.
Another possibility is that this society could exist undisturbed, and thus without human influence. According to researchers, chimpanzees are highly susceptible to human diseases.
The new findings allow researchers to better understand why menopause exists and how it developed in humans.
