The Wildlife Conservation Society has recently completed a study concluding that jack rabbits have quietly disappeared from the Greater Yellowstone Ecosystem. The Greater Yellowstone Ecosystem encompases riparian and mountainous terrain in and around Yellowstone National Park. It extends beyond the official boundaries of Yellowstone and includes the nearby Grand Teton National Park as well.

The reason for the jack rabbits' disappearance is not known, though some possible causes of their disappearance include disease, harsh weather conditions, or predation. But since the rabbit population crashed without notice, there is no data to clarify what caused their disappearance. The last confirmed sighting of a jack rabbit within Yellowstone National Park was in 1991. Sightings outside of the park boundaries are equally rare. Since 1978, there have been only three sightings in the nearby Grand Teton National Park.

Since jack rabbits disappeared from the region without detection until now, scientists are uncertain what effects their absence has had. Jack rabbits are thought to have filled an important role within the ecosystem's food web. In their absence, predators such as coyotes and recently introduced wolves must turn to other sources to obtain their nourishment. This means there may be added pressure on juvenile elk, deer, moose, and pronghorn as predators look to alternatives to jack rabbit prey.

The Wildlife Conservation Society study was lead by Dr. Joel Berger, a professor at the University of Montana. The findings of Berger's team are published in the latest issue of Oryx.

Find out more:

• Down the Rabbit Hole (Wildlife Conservation Society)
• Yellowstone's Rabbits Have Vanished, Study Says (EurekAlert)
• Greater Yellowstone Ecosystem (Greater Yellowstone Coallition)

Photo © Joel Berger / Wildlife Conservation Society. Jack rabbits like these have mysteriously vanished from Yellowstone, a Wildlife Conservation Society study says.