Mouse sperm jump aboard the love train

Wood mouse sperm join together to reach eggs faster

source: Nicola Jones
New Scientist July 13 2002 p17

Male wood mouse sperm join together to reach eggs faster, according to University of Sheffield biologist, Harry Moore. Thousands of sperm use hooks to link together, like a long express train. This may give the sperm a better chance of getting to an egg than sperm from another mouse. The chains may have between 50 and 2,000 sperm, and their speed can be as much as 50% faster than one sperm travelling alone. Marsupials also have sperm that cooperate, in their case by swimming alongside each other. Guinea pigs' sperm joins in clumps, though it's not clear how this helps the sperm. The clearest case of sperm showing altruism, however, is shown in wood mice.