November 22, 2007

Male bears have job to do

Getting shot gets in the way


Males matter, too, at least when it comes to polar bears, says a new University of Alberta study.

Hunting strategies that focus on male polar bears could actually put populations of the bears at risk.

"What we're trying to point out in this paper is you have to be very careful of how many males you take out of the population. Males matter, too, because they are the ones who need to find the females and impregnate them," said Peter Molnar, a biological sciences PhD student.

Polar bears roam over large tracts of land without any established territory and when mating season rolls around, it's up to the males to find females in the vast areas.

If there are fewer males, the chances of a male finding a female get lower, leading to decreased birth rates.

"The longer it takes to find them and the less males you have to mate with several females, the more you are going to run into trouble," said Molnar, whose work was published yesterday in the prestigious British-based science journal, Proceedings of the Royal Society.

Molnar - who worked with Dr. Mitchell Taylor from the government of Nunavut to gather data on polar bear populations at Lancaster Sound northwest of Baffin Island - said it's very difficult to say what the optimal sex ratio between males and females should be for polar bears.

Unlike other animals, the ratio is constantly changing based on population density. A high population density means males have an easier time finding females.

Molnar said the current strategy of hunting two males for every female may need to be carefully looked at and compared with population densities.

There is, however, no evidence polar bear populations are declining because of a lack of males, although Molnar says that is a future possibility.