[Yair Doza (OP)]

I remember hearing of a connection between the sexual behavior of primates and the speed of the male sperm.
It go like this - the more promiscuous the behavior, the faster the speed of sperm, so chimpanzee sperm is faster than human sperm which is faster then gorilla sperm.
Any of you know of this theory or know of data supporting it?
Thanks Yair

[RD]

... the size of the testicles is a reliable measure of the level of promiscuity across primate species.

The greater the promiscuity, the larger the testicles relative to body size.

For example, male gorillas have relatively small testicles and the female of the species is highly monogamous.

In contrast, chimpanzees are highly promiscuous and the males tend to have testicles that, in relative terms, are ten times the size of those of gorillas.

Human males are somewhere between chimps and gorillas.

This suggests that ancestral humans were not as promiscuous as chimpanzees - but neither were they entirely monogamous.

Dr Amin Gorgy, clinical director of the London Fertility Centre, said he was yet to be convinced by the concept of sperm competition.

However, he said other scientists believed that men produced two types of sperm - one to fertilise the egg, and another to fight off sperm from other males.

http://news.bbc.co.uk/1/hi/health/681172.stm