Evolutionary Clock Ticks for Snowshoe Hares Facing Climate Change

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New research from NCCWSC-funded scientists at North Carolina State University and the University of Montana shows that the evolutionary clock is ticking for snowshoe hares, which may not be able to keep up with the seasonal shifts caused by climate change.

Image: Climate Change and Snowshoe Hares Winter White Fur

Snowshoe hare experiencing camouflage mismatch in the spring at the Seeley Lake, MT, study site.

(Credit: Dr. L. Scott Mills (Research Photo), North Carolina State University. Public domain.)

New research from NCCWSC-funded scientists at North Carolina State University and the University of Montana shows that the evolutionary clock is ticking for snowshoe hares, which may not be able to keep up with the seasonal shifts caused by climate change.

Snowshoe hares rely on camouflage for protection, changing their coats from brown in summer to white in winter. This only protects them, however, when snow cover comes and goes each year on the same schedule.

Based on an article published this week in Ecology Letters, changes in snow timing and duration due to climate change are deadly for snowshoe hares. White hares stand out like "light bulbs” against snowless backdrops, presenting an easy target for predators. The researchers collected data from radiocollared snowshoe hares in Montana and found that mismatched hares suffer a 7 percent drop in their weekly survival.

“This paper shows that the mismatch costs are severe enough to cause hare populations to steeply decline in the future unless they can adapt to the change,” says lead author Marketa Zimova.

While individual hares cannot modify their molt timing or behavior, different hares molt at different times, enabling natural selection to favor those with molt schedules better suited to new snow patterns. Evolutionary change is slow, however, so the researchers recommend management actions that promote adaptation.

Learn more about this new study in the NCSU Press Release.

This research was funded in part by the USGS National Climate Change and Wildlife Science Center. Lead author Marketa Zimova also received support from the Southeast Climate Science Center. Learn more about the team’s work here.