BOB HIRSHON (host):
Cooperative sperm…I’m Bob Hirshon and this is Science Update.
Many mammals are polygamous and mate with more than one partner. As a result, sperm from different males compete to fertilize the female’s egg. According to Harvard evolutionary biologists Heidi Fisher and Hopi Hoekstra, one way they do this is by clumping together to outrace the sperm of other males.
HOPI HOEKSTRA (Harvard University):
Clumps or trains of sperm will actually swim faster than individual sperm.
Hoekstra says they observed this clumping behavior in the sperm of a polygamous deer mouse species.
The sperm don’t just clump with other sperm that they run into. They actually preferentially clump with sperm that are more closely related to them. That means that sperm can actually discriminate, they can tell which sperm they’re most closely related to.
She says they don’t yet know how the sperm recognize their relatives. I’m Bob Hirshon, for AAAS, the science society.