Color-changing hares in Montana are canaries in the climate-change coal mine. According to research published in the Proceedings of the National Academy of Sciences, wildlife biologist L. Scott Mills and his colleagues tracked the coats of snowshoe hares, which evade predators in part by turning white in the winter and brown in the summer. As Science Magazine reports the dates at which they begin changing colors have stayed more or less fixed, and so their only recourse against later snows and earlier springs is an ability to slightly speed or slow the color-change process.
That ability won’t be enough to keep them in sync with future winters, Mills found. He and his colleagues used more than a dozen climate models to determine the temperature and likely snow duration in the study area for 2050 and 2099. By midcentury, the snow season will be a month shorter, and by the end of the century it could be up to 2 months shorter, they report. With the initiation dates for molting fixed, that shift would result in hares being mismatched for as much as 36 days by 2050 and for double that amount of time by the end of the century.
There is, though, a figurative silver lining to the hare’s coat-color conundrum, according to Mills.
He suspects that they will be very easy prey, which is good and bad news. The bad news is that a lot of hares will die. The good news is that there will be a lot of pressure on the hares to evolve a new calendar for molting. Already, some hares in different parts of the country change color at different times of the year, and a few living on the Pacific coast don’t change at all. “It makes me optimistic that they can adapt by evolutionary change,” Mills says.
Evolutionary change as a solution to climate change–that is optimistic.