Speedy Sperm

Guys will do just about anything to make sure they find a good mate. And this is especially true in nature, where the signs of competitive mate selection are broadcast loud and clear: an impressive rack of antlers, a peacock's tail, an attractive mating call. But competitive mate selection can also drive some more subtle effects. Dr. Sigal Balshine, a behavioural ecologist at McMaster University, has been studying competitive mate selection in a family of African fish, called cichlids. She's found that male cichlids that must compete for access to a female, develop longer, strong and faster-swimming sperm than males that don't face as much competition.