Why do human females have menopause?

Recently a friend of mine asked me this interesting question. Untill now, I had not thought about this issue that much. Little did i realize i was going to step on a much debated question in evolutionary biology. First question – do animals experience menopause? The Wikipedia says Pilot Whales do experience menopause. Okay, what if this is an aberration like the human female? As i was researching on this topic, I came across this brilliant article “Why Women Change” by none other than my favorite author Jared Diamond. After proceeding to demolish the standard answers that are offered for this question, he masterfully concludes that it is because the benefits of menopause far outweighs the costs – less risk of child birth, you want the older women to be there to take care of the families etc.  He goes on to tie it to the menopause in Pilot Whales because they are also similarly social, highly intelligent animals. He wrote this article in 1996. Nearly 10 years later, in December 2005, Livescience carried a report that showed that Guppies (fish) experience menopause as well. But interestingly, female Guppies don’t stay around to take care of their litters. So the theory that menopause has been evolved for better protection of young ones seems to be incorrect. The livescience report goes on to say:

Menopause has been observed in other animals like Japanese quail, laboratory rats and mice, opossums, and other primates such as gorillas,
but most of these animals lack well-developed family networks and engage in
very limited, if any, maternal care. 

On the other hand, female lions and baboons—animals which rear dependent young and live in complex social groups like humans—don’t experience menopause at all and die soon after giving birth to their last young.

As for me, i am still confused, why does menopause occur? What do you all think?


  1. Anonymous said February 9, 2007, 8:52 pm:

    After reading your post, I thought that if Menopause had to be explained in terms of survival of species, these animals should live long enough to help in the process. I was typing a question, “how long do these other animals survive after menopause”. I decided to do a search my self and came across the same article which you had linked in your post. I found these observations rather interesting.

    However, one swallow does not make a summer, nor does one sterile female constitute menopause. Establishing the existence of menopause as a biologically significant phenomenon in the wild requires far more than just coming upon the occasional sterile elderly individual in the wild or observing regular sterility in caged animals with artificially extended life spans. It requires finding a wild animal population in which a substantial proportion of females become sterile and spend a significant fraction of their life spans after the end of their fertility.

    But human female menopause remains sufficiently unusual in the animal world that its evolution requires explanation. We certainly did not inherit it from pilot whales, from whose ancestors our own ancestors parted company over 50 million years ago. In fact, we must have evolved it after we separated from the apes just 7 million to 5 million years ago, because we undergo menopause whereas chimps and gorillas appear not to (or at least not regularly).

    There were few other links which gave some interesting insights

    Evolution of the human menopause.

    A hypothesis for the origin and evolution of menopause.


    “There may be little advantage for an older mother in running the increased risk of a further pregnancy when existing offspring depend critically on her survival.”

    “Results of a mathematical model are presented which show that reproductive senescence can be advantageous even when maximum potential lifespan is only 50 years, if the premature cessation of reproduction allows females to moderately increase the survival and fertility of their existing subadult offspring.”

  2. Anonymous said February 10, 2007, 2:17 am:

    That is right Archana. As i pointed out, jared diamond does make a powerful argument. But then as i also pointed out, what explains Guppies and other animals listed showing menopause. These are not the occasional sterile animals that Jared Diamond dismissively says but clear cases of animal menopause. I thought i was bought into Diamond’s argument but then this dismissiveness on sterile animals drove me to research this further and i chanced upon the Guppy study report. So I can only reasonably conclude that human menopause is just another animal menopause that some animals have for no apparent reason other than longevity of life or some other reason to be figured out. It is not some special human thing.

  3. Anonymous said February 10, 2007, 4:03 am:

    I understand that Sukumar. I was wondering about the length of time they survive after Menopause. Jared Diamond also makes the point they need to be alive for “significant fraction of their life spans after the end of their fertility”. If these other animals underwent menopause and lived long enough to be noticeable, how come most scientist are discovering it only now?

  4. Anonymous said February 10, 2007, 6:26 am:

    That is right Archana. Post-menopausal longevity is an important one. But the crux of the theory is what is popularly called “grandmother hypothesis” that is menopause is their for women to take care of their children and grand children. This also means that women will hang around with the family post menopause to take care of the family. The problem is – Gorillas which also have menopause and have sufficient post-menopausal longevity actually leave their family groups. So then the grandmother hypothesis doesn’t apply to Gorillas.

    As to why scientists didn’t observe it, there are a variety of reasons including funding for research and hot research interests. This may not have been a hot field for focused research. Also, you could ask the same question of so many XYZ findings that come every day – why are the scientists finding this XYZ thing now? Don’t know how you answer that except that we don’t know a lot of stuff about the universe and we will find new stuff every day for the foreseeable future and still no develop a complete understanding.

  5. Anonymous said February 10, 2007, 6:46 am:

    Animals living past their reproductive age would be a fairly obvious thing to observe, I thought.

    Definitely agree, we are yet discover so many things, we can’t be asking why we did not discover them yet.

  6. Anonymous said February 11, 2007, 12:07 pm:

    Thanks Archana. Don’t know why it is difficult, but my guess is that to track animals in the wild over a long period of time must not be easy.