Do Orangutans Undergo Menopause?
It was recently reported that scientists observed menopause in a 49-year-old female orangutan, calling into question the assumption that humans are the only apes to undergo a natural end to female fertility. Gina, a wild-caught orangutan who has lived at the Durrell Wildlife Park in Jersey for the past 46 years, where she has given birth to 7 offspring, was being examined by vets in preparation for breeding when they discovered the physiological signs of menopause.
What did the media say?
The Daily Mail reported this story in a relatively objective way. However, they preceded the story with several bullet points, the final of which read, “Humans and orangutans share 97.6 per cent of their DNA, but it was thought menopause was a sign we were significantly more evolved”. The BBC article also repeated this idea; but there are a couple of things wrong with this statement. First, although humans were thought to be the only apes to undergo menopause, they are certainly not the only mammals to undergo menopause. Orcas (“killer whales”) can end their reproduction up to 50 years before the typical end of their lives. Pilot whales also undergo menopause. One of the biological hypotheses for the function of menopause, the grandmother hypothesis, was discussed in a recent post on Research the Headlines. The second problem with this statement is that it perpetuates the myth that organisms are related in a hierarchy or ladder of evolution, with humans at the top being the most evolved. Humans didn’t evolve from orangutans or chimpanzees; we all share common ancestor species. In other words, the different ape species are like cousins and second-cousins, each being equally related to a shared grandparent or great-grandparent.
What does the research say?
Although described as research, the reported finding is currently only an anecdote, which will be described in more detail in an upcoming documentary. There has not yet been a published, peer-reviewed paper on the phenomenon.
So is menopause actually more widespread among apes than previously thought? This new data is intriguing, but it is only a single case study. The researchers have not seen any signs of pathology that would have led to menopause, but it is not possible to entirely rule out the possibility that this is a unique case among orangutans. However, now that we know it is a possibility, other researchers can also look for signs of menopause in captive and wild female orangutans. Such research could provide important data to assist with breeding programmes for this fascinating and endangered species.