Climate Change & Animal Camouflage

Apr 20, 2017
Originally published on April 25, 2017 2:26 pm

The coats of around 20 animal species go from brown in the summer to white in the winter.  Researchers are studying whether climate change is causing those animals to adapt.

“It (the change in coat color) is driven by day length.  They turn white at the same time of year regardless of whether there is snow on the ground. And that’s always worked through evolutionary time to match them to the snow,” said Dr. Scott Mills, Associate Vice President of Research for Global Change and Sustainability at the University of Montana. 

“But now we’re finding as the number of days with snow on the ground decreases, you have more and more days with these white light bulbs – these white animals – hopping around or moving around on a brown, snowless background.”

Mills , who was in Macomb to give the Roger & Jean Morrow Distinguished Lecture sponsored by the Department of Biological Sciences and the College of Arts & Sciences at Western Illinois University, said researchers want to know whether the animals can adapt quickly enough to avoid huge losses in population. There are no signs of such losses so far.

He said animals can adapt by moving, by changing behaviors, or through natural selection that causes them to stay brown longer into the fall and change back to brown sooner in the spring.

“We’re throwing the kitchen sink at investigating all of them.  We’re using field work, we’re using genetic tools, we’re using computer tools, we’re using captive studies. We’re really trying to understand this scope for adaptation, which really has not been very well studied,” he said.

Mills is studying snowshoe hares in western Montana, but he said studies of animals that go through annual coat color changes are being done around the globe.  Those animals include arctic foxes in Sweden and weasels all around the globe. He said his own studies of the issue began seven or eight years ago and came about by accident.

He said he started studying snowshoe hares in the late ‘90s because the hares are the main prey for Canada lynx, which is a threatened species. Mills looked into whether logging jeopardized the natural habitat for snowshoe hares, which would have a domino effect on the lynx.

“So I started out studying snowshoe hares by trying to figure out better ways to do logging practices that allow snowshoe hares to persist in the face of logging.”

Mills said over time he and fellow researchers noticed more and more instances of white hares hopping around on brown backgrounds and that got them thinking about why that was happening.

Mills said Montana now has 10 fewer days with snow on the ground than it did 20 years ago. He said projections estimate that in the next 50 to 100 years, Montana might have 30 to 50 fewer days with snow on the ground. 

“That sounds striking but I tell skeptics that they should talk to the ski industry because the ski industry people have absolutely no doubt that this is happening and they are very much planning for this,” Mills said.

“And the Department of Defense spends a lot of time thinking about climate change because they also realize that there are implications.  So it’s real.”

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