Cads of the savanna
Male topi antelopes lie to get the ladies
By Rachel Ehrenberg
Web edition : Friday, May 21st, 2010
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But baby, there's a lion over thereWhen a female topi antelope (right) starts to wander from a male’s territory, he snorts and stares as if a predator is nearby, even when there’s no danger.Bro-Jørgensen et al./American Naturalist 2010
As any dating woman knows, men can be dogs — but a new study suggests antelopes might be a better fit.
Male topi antelopes will resort to deception to keep a potential mate around, snorting as if there’s a lion nearby just when it seems she might wander off. The discovery is the first report of outright mate deception in an animal other than Homo sapiens, a research team reports in the July American Naturalist.
Some mother birds will feign a broken wing to lure a predator away from their nest, and there are reports in animals such as monkeys and squirrels of males deceiving other males in the heat of competition. But the male antelope behavior “is the clearest example of tactical deception between mates in animals other than humans,” comments Cornell University’s H. Kern Reeve, an expert in the evolution of cooperation and conflict in animal societies. “This is quite interesting.”
Study leader Jakob Bro-Jørgensen discovered the devious behavior while studying topi antelopes on the savannas of the Masai Mara National Reserve in Kenya, where during the spring mating season males stake out territories rich in grass. The female antelopes are sexually receptive for one day only, and they spend that day visiting several males, munching grass and mating.
Bro-Jørgensen noticed that when a female would start to wander away from a male’s territory, the male would look in the direction she was headed, prick his ears and snort loudly — the same snort the animals use when they’ve noticed a lion, leopard or other approaching predator.
“It was quite funny — it made me laugh,” says Bro-Jørgensen, an evolutionary biologist at the University of Liverpool in England. “It’s such an obvious lie — clearly there’s no lion.”
Suitors in nature commonly exaggerate their virtues. But this work documents a rare situation in which evolution favors outright lying in the mating game, says Reeve. The cost of the lie is minimal to the male antelope — he merely snorts. But the cost to the female of ignoring the lie could be great — if there truly is a predator nearby, she’s dead.
To test whether the males were lying outright, Bro-Jørgensen and his colleague Wiline Pangle of Ohio State University in Columbus first observed males when they were making honest snorts. Male antelopes snorted when a human was approaching, the researchers found, even if an antelope was alone. This suggests that rather than being a warning to fellow antelopes, a true snort is actually directed at the predator itself.
This makes sense, says Bro-Jørgensen. If they have enough of a head start, topi antelopes can outrun lions and even cheetahs. By snorting at a cat who thinks it’s hidden in the grass, an antelope says, “I see you predator — give it up.”
The researchers also recorded true and false snorts and played them back to female antelopes, to see if the ladies could tell the difference. Judging by their reactions, the females couldn’t tell true from false snorts. Neither could an audio analysis by the researchers, which detected no acoustic differences that might tip off female antelopes.
The clincher that the males were lying to get lucky came from observations of the animals in action. A male antelope secured two to three more chances at mating with a restless female if he pulled the false-snort trick, says Bro-Jørgensen. When receptive females were in males’ territory, the researchers heard the males emit as many as nine false snorts for each honest one.
But even antelopes can cry “lion” too many times. “If the male keeps making false alarms and there’s no predator,” Bro-Jørgensen says, “she walks away in the end.”
