Jackrabbits Vanish from Yellowstone

Take a drive through a western state some evening, when the light slants down over the sagebrush, and watch for jackrabbits. Whether they're sitting motionless, TV-antenna ears pricked, or loping down the dusty roadsides, they're part and parcel of the wide open spaces.

So it's staggering to learn that white-tailed jackrabbits have all but vanished from two of our iconic western parks: Yellowstone and Grand Teton. Together, these two parks are a riot of wildlife at the center of the vast Greater Yellowstone Ecosystem, which stretches 20,000 square miles across Wyoming and adjacent Idaho and Montana.

Mysteriously, the hares just faded away, unnoticed, sometime in the middle of the last century - under the noses of sightseeing tourists and eagle-eyed field biologists. You can kind of imagine how the world could lose an earwig species, perhaps, or maybe a fungus beetle, while it wasn't looking. But a large, cute mammal so abundant it was once made into coats? Even stranger, jackrabbits are still numerous--and hunted--in other parts of their range.

Ecologist Joel Berger reported the vanishing act after studying 130 years of historical records, museum databases, reports from field biologists, and analyses of an enormous number of coyote droppings. Berger's research (the paper is not yet online) turned up only one jackrabbit sighting in Yellowstone since 1990 and five in Grand Teton and Jackson Hole since 1978, according to his paper. Reports from the 1920s and 1930s pegged the hares as fairly common, and then the sightings ceased. Coyote scat told the same story: droppings contained 10 percent hare hair in the 1930s, 1 percent by the 1970s, and none by the late 1990s.

The tourists that flock to these parks each summer tend to point their cameras at bigger animals. But big game like pronghorn, bison, elk, and moose could feel repercussions from a dearth of jackrabbits, Berger suggested. With fewer rabbity morsels to prey on, coyotes could well turn to the young of larger animals, as has already been noted in parts of Montana, Wyoming, and South Dakota, according to the paper.

Perhaps more worrying is what the disappearance says about our ability to judge how well conservation is working. If species disappear without our knowledge, we run up against the problem of a shifting baseline. It's a form of blissful ignorance: Only by having a complete record of the past can we judge how much the world of the present is changing (for more on shifting baselines, see the blog of the same name).

As for white-tailed jackrabbits, they're far from extinct at the moment. Berger advocates reintroducing them to Yellowstone and Grand Teton, both to restore the ecosystem and to allow us to witness the ways these (nearly) pristine places change as jackrabbits return. We might learn something new. But it won't be a matter of simply pulling them out of a hat.