Bats and balls
By London
December 8, 2005BIG testicles go with tiny brains, according to a new study of bats. The discovery suggests that a biological trade-off has to be made between brains and sperm. Because of high energy demands, males cannot generate large amounts of both, scientists believe.
In many bat species, females are unusually promiscuous, so natural selection has led to males evolving enormous testicles — at the expense of their brains. Their genitals of some bats make up 8.5 per cent of their body mass.
The testicles of apes range from 0.02 per cent to 0.75 per cent of body mass.
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