Global warming changes animals' hibernation patterns

Changes in snowfall, summer precipitation, and ambient temperatures attributed to global warming could affect the survival of hibernating species such as groundhogs, marmots, and ground squirrels, says Colorado State University researcher Greg Florant.

Florant, a professor of biology, has teamed with Penn State University researchers to determine whether animal torpor patterns – periods of reduced physical activity, body temperature, and metabolism – are genetic or can be manipulated by environmental temperatures.

Sleeping on the job

The researchers collected groundhogs from Maine, Pennsylvania, and South Carolina and brought the specimens to Florant's lab at CSU. The controlled-temperature lab will help the scientists assess behavior differences in the lab environment, such as animals awaking earlier than others. Generally, animals in colder climates spend more time in hibernation than their counterparts in regions farther south.

"We do know that there are definite changes in torpor patterns among the animals in their natural environments," Florant said. "The question now is: Will we see these changes in the lab?"

Weather effects

Hibernating animals such as groundhogs traditionally are seen as predictors of weather, says Florant. However, these animals can teach researchers more about the complex behavior of hypometabolism – a regulated decrease in metabolic rate – in which animals can turn off their appetites and slow their breathing to a point that would be lethal to other animals.

The effect of climate change on hibernating animals already can be seen. Yellow-bellied marmots are emerging 38 days earlier than 23 years ago, apparently in response to warmer spring temperatures at the Rocky Mountain Biological Laboratory near Crested Butte, Colo., according to research at the University of Maryland.

Increases in global temperatures will affect the amount of time animals spend hibernating. If animals increase their metabolism before plants have begun to sprout, they could die from starvation.