The Sperm’s Tale – The Evolution of Promiscuity

Professor Tim Birkhead from Sheffield University asks whether promiscuity is favoured by evolution and why sperm have to do battle in different ways to achieve success in fertilization in lots of different environments.

Sperm

The conditions they have to work with are often governed by the behaviour patterns of the species concerned. Some female birds even eject the sperm of a lesser male if one they fancy more becomes available later. The poor old sperm has a hard time. We discussed his “life and mission” and his “friends and enemies” in his battle to be the one that wins “the egg and sperm race”.