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Grizzlies facing lowest birthrate

CALGARY, Alberta – Female grizzly bears are producing the fewest offspring ever in North America, a study said.

The low birthrate for grizzlies coincides with the encroachment of the Banff National Park, according to the 9-year study made public Thursday.

The study of 71 bears from 1994 to 2002 also found that humans were responsible for more than 75 percent of female bear deaths and 86 percent of male deaths in the same time period.

Female grizzlies do not reproduce until they are 8 years old and generally have one or two cubs every four or five years.

So the death of a single bear can have a significant impact on population.

“Basically, we (need) to have 19 out of 20 adult female bears in their reproductive years to survive into the next year,” said Stephen Herrero, an environmental scientist at the University of Calgary and co-author of the study.

“It’s a tricky balance we’ll have to maintain.

“This is definitely a wake-up call – this says we have to be very careful with mortality, because these bears are going to bounce back slowly, if at all,” Herrero said.