Cooperative sperm outrun loners in the mating race
Swimming in groups helps sperm stay the course in the reproductive tract
Even sperm gotta stick together.
Bull sperm swim more effectively when in clusters, a new study shows, potentially offering insight into fertility in humans. In simulated reproductive tracts of animals like cattle and humans, the behavior increases the chances that groups of cooperative bovine sperm will outpace meandering loners as they race to fertilize a female egg cell, physicist Chih-kuan Tung and colleagues report September 22 in Frontiers in Cell and Developmental Biology.
The benefits of clustering don’t come down to flat-out speed. “They are not faster,” says Tung, of North Carolina Agricultural and Technical State University in Greensboro. “In terms of speed, they are comparable or slower” than sperm traveling alone. Like the sperm equivalent of herds of tortoises racing individual hares, the winners are not necessarily the swiftest but rather the ones that can stay on target.