Monogamy: Honorable But Lethal?

June 18 -- Monogamy may seem romantic, but for some animals it could be a hazardous way of life.

New research has revealed a surprising link among mammals living on reserves in Ghana: Those with fewer mates are at higher risk for extinction. The finding suggests that conservation efforts might be better focused on those more vulnerable animals that stick to one or a few mates.

It could also mean that monogamy, which is already rare in the wild kingdom, may be a fading trait.

"In avoiding extinction, it pays to be promiscuous," said Justin Brashares, a conservation biologist at the University of British Columbia in Vancouver, Canada, who published the study in the recent issue of the journal Conservation Biology.

Fate of the Faithful

Brashares analyzed the population levels of large mammals in six reserves in the savannas of Ghana, where rangers have kept careful records of animal populations for more than 30 years. In that time, 78 species became locally extinct, largely due to human factors including hunting and loss of habitat.

He found that most of the lost animals shared at least two traits — their populations were isolated and the males mated with one or just a small group of females.

Among the fated faithful were species of duiker, a small, monogamous antelope, which died out within 10 years after each reserve was established. Also doomed were many species of colobus monkeys, which stick to one or a small group of two or three mates.

Meanwhile, African buffalo, whose males preside over harems of about 15 females, are still thriving, as are green monkeys and baboons, which are highly polygamous.

"We often think of large-bodied animals as the ones that are most endangered," said Brashares. "But species like elephants and buffalo are doing better."

Brashares says his work points to the need to focus conservation efforts on animals that keep their sex lives simple.

"We barely have the resources to monitor just a few species, so I'm always looking for traits of species that can help direct our resources," he said.