Girl-Fight in the Serengeti

25 June 2002 (All day)

Oh no you don't. A female antelope prepares to interrupt a rival's tryst.

Everybody's in it for the sex. That's the unexpected conclusion of a new study of antelope. In an early online edition of the Proceedings of the National Academy of Sciences appearing the week of 24 June, a biologist shows that it's not just horny guys who battle for mates. Females throw their weight around, too, and that has promoted the evolution of a spectacular arena where both male and female antelopes gather to compete.

Mammals spend a great deal of time and energy fighting for--and trying to impress--their mates. Examples abound of showy and spectacular male competition. According to conventional wisdom, males do most of the fighting, and the strongest win the females. To test this assumption, Jakob Bro-Jørgensen, a biologist at Stirling University, U.K., observed the mating behavior of topi antelopes in Africa for 2 years. Topi antelopes meet on the lek, an arena where show-stealing males clash horns. Researchers figured that while males duke it out, females hang around to reap the region's potential side benefits: protection from predators, less harassment from loner males, and more nutritious grass.

None of these benefits turned out to exist when Bro-Jørgensen statistically compared the situation on- and off-lek. According to his data, a female on the lek is more likely to be threatened by hyenas, more likely to be harassed by a sex-crazed male, and less likely to find a decent meal on the hoof-worn turf. So why bother? Bro-Jørgensen proposes that females flock to male competitions to allow them to fight for favored males. Bro-Jørgensen observed females tussling with the studliest males to distract them from other frisky females and sometimes even charging in to interrupt coitus.

The study has convinced Alatalo Veli, a biologist at the University of Jyväskylä, Finland. Because the strongest male antelopes mate with only a few partners, the female's need to compete for the best males helps drive the lek-forming behavior, says Veli. Charles Darwin, of course, was the first to argue that females could shape evolution by their choices. According to Veli, the new work proves that females don't always stand on the sidelines.

Related sites
All about leks
All about antelopes

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