No other
mammals studied (with the possible exception of
pilot whales) are known to commonly cease their
reproductive abilities in nature.
One of the theories of why human females go through menopause is called the ‘grandmother hypothesis’. This theory can also account (if not partially, almost fully) for the evolution of the human species.
We are unique in that we do not reproduce up until we die, like our ancestor apes. Apes- the older they become the more likely it is for them to die during child birth. With the onset of menopause this is humans is reduced. The human female goes through menopause at about the age of 40-50 years old, when dying during child birth becomes much more dangerous. With her reproductive abilities put to a halt, the wisdom and knowledge that has been accumulated is put to use, to be passed onto younger humans. This allows the mothers to put more time into their children and to watch their children grow up and have children of their own. During this time after menopause the mothers would have been reproductively better off helping their children (who shared their genes) than they would have been reproducing themselves. This all boosts the survival of the species.
Menopause has helped us to evolve to become who we are today.
Of course, this is all just a theory, and there are people who don’t agree.
Lerner, M. Is there evolutionary reason for menopause? Star Tribune 1998 April 23 says that:
"Study concludes that recent theories on menopause--that it allows grandmothers to help raise the younger kin and therefore boost the survival of the species--is wrong and that there is no reason for menopause. The study is based on research with lions and baboons."
Sources and for more information:
http://faculty.knox.edu/fmcandre/development.html
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?holding=npg&cmd=Retrieve&db=PubMed&list_uids=7925746&dopt=Abstract