A mule deer’s defining characteristic is its large ears, which are about three-fourths the length of its head.

After a long winter—which still seems to be hanging on in some places—people are understandably anxious to get outside and get on the move again. Perhaps we take our cue from the nonhuman animals, which have for millennia followed spring migration routes. And one of the places where a lot of this “moving about” is taking place is in the Greater Yellowstone Ecosystem, the scene for some of the greatest migrations in the world.

Among those flows of wildlife is the famous 120-mile pronghorn migration from the Upper Green River Basin into Grand Teton National Park. Others include nine major elk migrations that radiate out of Grand Teton and Yellowstone National Parks and the surrounding wilderness areas; and—in some really exciting news—the recently discovered 150-mile, Red Desert mule deer migration. It’s the longest ungulate migration in the Lower 48.

The video shown below, published in 2014, describes this migration. Our learning about it began with a research study of what was thought to be a resident, nonmigratory herd of mule deer. But, surprisingly, with the aid of advanced GPS technology, the researchers verified that the herd, consisting of nearly 5,000 animals, actually travels more than 100 miles north to the boundary edges of northwest Wyoming.


It was recently discovered that a mule deer herd in the Greater Yellowstone Ecosystem migrates 150 miles in the spring.

The phenomenon was hidden in plain sight, according to photojournalist and National Geographic grantee Joe Riis, who created this video to give you an idea of how tough a migration can be. These mule deer have to move across three highways, over 100 fences, and through multiple reservoir and river crossings—all on public and unprotected private lands.

The hardships the deer undertake mean so much more, though, than just getting from place to place. Migrations connect forestlands to parklands to working lands. They show us what wildlife knows instinctively and what we humans seem to have forgotten: that political boundaries mean nothing to the planet’s true nature.

Here’s to finding your true places and natural habitats,