If female bats mate with more than one male, a sperm competition begins. Males want to make sure their genes make it to the next generation. And evolution is all about tradeoffs. |
If female bats mate with more than one male, a sperm competition begins. The male who ejaculates the greatest number of sperm wins the game, and hence many bats have evolved outrageously big testes. |
It turns out size does matter. |