Sperm form pelotons in race for life

Scientists have found that spermatozoa have a propensity to swim together as they race to be first to fertilise an egg, and that – like Tour de France riders – doing so seems to boost their chances of success.

Chih-Kuan Tung, from North Carolina A&T State University, watched bull sperm through a microscope as they navigated a simulated female reproductive tract. He saw the sperm freely leave and join different clusters.

‘‘This may resemble the peloton formation in biking,’’ Tung said, ‘‘although the fluid mechanics for sperm is drastically different.’’

His research, published in the journal Frontiers in Cell Development and Biology, offers some explanations for the phenomenon, known as ‘‘sperm clustering’’.

It may be that gathering in numbers offers a navigational and endurance advantage. In Tung’s model reproductive tract, the clustered sperm were better able to keep a straight path and resist being swept away. He did not see a speed advantage, however.

Tung said the work could have relevance in investigating unexplained infertility, and perhaps in selecting the best sperm for IVF treatment.