The Heat Is Online

Squirrel Reproduction Altered by Warming

Study: Global Warming Affects Squirrel Reproduction, July 23, 2003

July 22, 2003  University of Alberta researchers recently concluded a 10-year study showing that red squirrels in the Yukon are reproducing earlier in the year in response to global warming and thus being genetically affected by it.

The researchers, who studied the mating habits and DNA of more than 5,000 female red squirrels, found that litters were being born an average of three weeks earlier than they historically had been.

"We've been the first to show that this is a genetic change ... and not just behavioral change," professor Stan Boutin, who led the team that conducted the study, told a Canadian Broadcasting Corporation reporter.

According to Boutin, the "squirrels that breed earlier to take advantage of the warmer weather have more access to food and territory." Therefore, their offspring are more likely to survive and reproduce.

"You've got the positive aspect showing that animals are adapting to changes in climate," said University of Victoria climate researcher Andrew Weaver. "On the other hand, you have questions as to how much can [animals] adapt, and what does that mean 50 years from now when things get warmer still?"