How climate change plays havoc on hibernating animals
Humans may be up and playing in the snow all winter, but many other mammals are hibernating or going into a dormant state of torpor. Climate change could affect how they do that, though.
Hibernation is generally used to survive brutal environments, a lack of food, or both. Some respond to environmental factors like temperature, sunshine or hunger.
“Those are facultative hibernators,” explained Sarah Mohr, a graduate student in neuroscience at Yale. “The truest, most extreme form of hibernator is called an obligatory hibernator. These are animals that will enter hibernation on a strict seasonal cycle, but cannot be induced to enter hibernation by changing their environmental conditions or their food and water availability.”
Mohr said climate change can affect both kinds of hibernators, especially if it impacts food sources when they’re awake.
“If they’re unable to store enough food as fat – for example, if there’s a drought and there isn’t vegetation when they expect vegetation – they won’t be able to make those fat pads and they won’t be able to survive the winter,” she said.
Changing environmental signals have already started changing some animals' behavior, as a new video produced by the American Chemical Society – informed in part by Mohr's research – explains.
For example, some bears are waking up earlier. Some chipmunks aren’t even going into a dormant state. And the threatened northern Idaho ground squirrel is hibernating even longer.
Those ground squirrels can hibernate up to nine and a half months a year, according to Austin Allison, a University of Idaho master's student.
“And the squirrels seem to be using snow as a cue for determining when to exit hibernation, when to emerge in the spring,” he said.
There’s been more late-season snow around the squirrel’s small territory in recent years, which means more time hibernating and less time to store enough fat to survive their dormant state.
“This whole system of hibernating, emerging, stuffing your face for a few months, and going back into hibernation only works when you have seasonally predictable climates,” he said.
The warming climate means parts of the West are expected to receive far less snow in the future though, which Allison said could signal ground squirrels to wake up sooner. And that means more time trying to escape predators.
“These squirrels are actually a prey item for a wide array of predators,” he said. “But most of those predators aren’t able to capture squirrels underground, and they hibernate two feet underground.”
All that said, it’s hard to say exactly what climate change will mean for hibernating animals. Each one is part of a very complex environmental web, which can be affected by geography and how other animals respond to climate change and so many other factors. It may be positive for some and negative for others.
Mohr at Yale pointed to the flexibility of the thirteen-lined ground squirrel. She said their hibernation period can vary depending on where they are, so species like that may be poised to adapt to climate change.
Ultimately, Mohr said we could even see new animals start using hibernation, while others use it less. Several animals have that capability.
One day, she said, it might even be useful for humans.
This story was produced by the Mountain West News Bureau, a collaboration between Nevada Public Radio, Wyoming Public Media, Boise State Public Radio in Idaho, KUNR in Nevada, the O'Connor Center for the Rocky Mountain West in Montana, KUNC in Colorado, KUNM in New Mexico, with support from affiliate stations across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting.
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