The young marmot in the video clip looks slightly dazed as it emerges from its burrow into a world of white. After hibernating for eight months, the marmot must be hungry, but snow still blankets the ground and there is not a trace of green anywhere in sight.

"They come out of their holes in mid to late May with no idea of what conditions are going to be like. They sometimes might have to wait two or three weeks before there is anything to eat," says Tim Karels, who has been studying hoary marmots in the Yukon's Ruby Range since 1999.

Karels' video footage shows a critical stage in the life cycle of these animals. If the snow melts quickly, adult marmots are more likely to reproduce and will probably bear more young per litter as well. If the snow lingers, fewer young marmots are likely to head into their burrows to hibernate the following fall.

So far climate change, which is causing spring to come earlier to northern regions, seems to be favouring this population of hoary marmots. In this four-square-kilometer study area, their numbers have surged from fewer than 20 in 1995 to about 150 today.

But Karels says that, with time, his research might show that big population swings like this one are just the marmots' way of coping with the severe environment which they call home. He suspects that these marmots might go through a ten-year population cycle, as do the animals that live at lower elevations in the boreal forest.

"Marmots have been around for a long time. They have to be adapted to these changes," says Karels, pointing out that marmots survived here through the Ice Ages and evolved here in North America.

Karels hopes that his research will shed light on how these animals respond to change, and possibly offer some ideas on how to help save one of the world's most endangered species, the Vancouver Island marmot, which is closely related to the hoary marmot.

While hoary marmots in the Ruby Range appear to be doing fine, only 25 Vancouver Island marmots still survive in the wild, and researchers are not sure why their numbers have plummeted so low.

Very little is known about hoary marmots, which live across Canada in a wide range of alpine environments. Karels is the first Canadian researcher to study them, and the last North American study was conducted 25 years ago.

Over the last few years Karels and his research team have surgically implanted data loggers that record internal body temperatures into 39 marmots. Last summer he removed four of the devices, and discovered that the marmots' body temperatures will drop as low as 2 degrees Celsius when hibernating.

"They are obviously very efficient hibernators," he says.

As many as 20 of these highly social animals will hibernate together in one burrow, and researchers think this strategy helps them survive through the long northern winters.

Karels is now trying to figure out exactly why the Ruby Range population is increasing in numbers. His research team is testing whether earlier access to food is the key by supplementing the spring diet of some marmots with rabbit chow.

If they find that the well-fed marmots produce larger litters, they might eventually try supplementing the diets of the Vancouver Island marmots as well. "It might be a low-cost solution for that population," says Karels, "though it would not be a long-term one."

Researchers in Colorado have found that a lack of food in spring affects the number of young born to yellow-bellied marmots. A 25-year-long study has found that these marmots are emerging from their burrows 38 days earlier than they did a quarter of a century ago.

Unfortunately the Colorado snowpack is not always melting a month earlier, so the marmots sometimes have nothing to eat for weeks at a time after emerging from their burrows.

In the Ruby Range the weather conditions have varied greatly over the last four years, giving Karels much of the information that he needs to start building a population model that can predict marmot numbers.

In general he thinks that marmots can survive a number of bad years when the snow melts late, as long as there is an early spring every few years to boost their numbers. "The ratio of good years to catastrophic years seems to be the key. Marmots are doing well now but that could change in 50 years," he says.

Karels says that it will take more time and research to tease apart exactly why the marmot population seems to expand and contract so drastically. "We are just starting to understand how these populations respond to weather in the short term," he says.

"As of yet we cannot determine if the increased number of marmots in the Yukon is a cyclic peak or a response to favorable climate change effects. We're trying to learn as much as possible, as quickly as possible, about how these populations work," he says.