Female chimpanzees living in a community in Kibale National Park in Uganda also experience menopause, a biological process that until now had only been documented in humans and some whale species.
But now, a team of scientists who observed this community of great apes between 1995 and 2016 have found signs in their females that show that they survive many years after ceasing to be fertile. The conclusions of this research led by Brian Wood, from the Max Planck Institute for Evolutionary Anthropology and the University of California, are published this week in the journal Science.
According to its authors, these signs of menopause in wild chimpanzees will help to better understand the evolution in humans of this process that is very rare in nature. And although women stop being fertile between 45 and 55 years in general – although the average age is between 51 and 52 years -, and they can live many decades without the ability to reproduce, The vast majority of females of other mammal species can have offspring throughout their lives.
Menopause begins when the eggs in the ovaries run out.. This cessation of ovarian function in turn causes a marked decrease in the levels of estrogen and progesterone, which are hormones produced by the ovaries, and a decalcification of the bones, which in turn leads to the appearance of the symptoms that accompany to menopause.
The benefits of this biological process are not at all clear, so it is a challenge for scientists to explain why women acquired this evolutionary trait. It also remains uncertain why menopause evolved in humans but apparently did not do so in any other long-lived primate. In this work, this team of scientists present demographic and hormonal evidence of menopause in wild chimpanzees after observing a total of 185 specimens in the Ngogo community for 21 years.