Snowshoe hares caught wearing the wrong color

 

I knew we were in trouble when I saw the third snowshoe hare. It was almost noon on the first day of elk season back in early November. I had a knife, hunting rifle and adequate ammunition. Yet what I realized made the hair stand up on the back of my neck. I felt immediately threatened. As we all are.

Here in Colorado, we have so far been spared the most dramatic consequences of climate change. No oceans are lapping at the shores of Denver and no glaciers are calving off Grand Mesa near Grand Junction.  Yet scientists warn that humans are responsible for creating a new geological era some have labeled the Anthropocene, whose warming atmosphere is tipping our world toward a more chaotic climate.

“It was taken for granted that the process was not something that could be observed in real time, an assumption that has now been proven false,” writes Elizabeth Kolbert in Field Notes from a Catastrophe: Man, Nature and Climate Change. In Ithaca, New York, she notes that four out of six frog species have begun to mate 10 days earlier every year, and at an arboretum in Boston, spring-flowering shrubs have advanced by eight days. In California’s Sierra Nevada, a butterfly named Edith’s checkerspot now lives 300 feet higher than it did a century ago.

Kolbert adds, “The planet has often been colder than today, but rarely warmer, and then only slightly.” She cautions, “It is only in the last five or 10 years that global warming has finally emerged from the background ‘noise’ of climate variability. And even so, the changes that can be seen lag behind the changes that have been set in motion.”

Elk hunting in Colorado’s magnificent high country, the last thing I had in mind was climate change. There had been a little early snow. My partner and I had topped the ridge by 9 a.m., seen elk tracks though not fresh ones, and we’d gone our separate ways.

I was on my way downslope when I saw my first rabbit. Pure white, the snowshoe hare quivered in a snowdrift next to fallen timber. He was doing his bunny best to be camouflaged but on that south-facing mountain the previous week’s snow had melted fast. Forty yards farther I spied bunny number two, with his nose twitching and pink ears swiveling. He ran off and hid near more snow, but he had to cross bare ground to do it. That was when I found the third rabbit, almost at my feet. He glared white against tan pine needles. Snowshoe hares should know better. Why were they white in early November with limited snow on the ground? What was happening?

“I’ve seen and had many reports the last three years about mismatched hares and habitat, mostly in the fall when hares are turning white before much snow cover,” says Scott Wait, the southwest region’s senior biologist for Colorado Parks and Wildlife. “But I’ve also seen white hares in the spring when some of our snow has melted from dust storm deposition leading to early snowmelt.”

Snowshoe hares survive by mimicry or camouflage, the species evolving to be brown in summer and white in winter. Wait told me, “Color change is initiated due to daylight length, which might be related to snow accumulation on an evolutionary timescale. If snow accumulation varies from normal, the hare continues to change color but might find itself wearing the wrong color, white on a brown background, or brown on a white background.”

So that was it: Snowshoe hares have adapted not to the amount of snow but to the length of daylight. That first weekend in November, there should have been more snow on the ground, but there wasn’t. The rabbits had planned on winter snow cover that had already begun to melt. I had seen climate change in action, or so I thought. Scientist Scott Wait wasn’t sure: “Are the mismatches seen by many elk hunters in recent years due to climate changes, annual variation, or merely an increase in hare abundance?”

No one knows for sure. Dr. L. Scott Mills at the University of Montana says that genetic variation may already be resulting in rapid rabbit adaptation to our changed environment.

Maybe, though not where I was hunting. I saw three bright white bunnies in small snow patches on an otherwise dull brown turf. I hope the rabbits make it through the winter, and I hope they can adapt to climate change. Us, too.   

Andy Gulliford is a contributor to Writers on the Range, a column service of High Country News (hcn.org). He is a professor of history and Environmental Studies at Fort Lewis College in Durango, Colorado ([email protected]).

Note: the opinions expressed in this column are those of the writer and do not necessarily reflect those of High Country News, its board or staff. If you'd like to share an opinion piece of your own, please write Betsy Marston at [email protected].

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