Story of Deer 255


The Wyoming Mule Deer That Traveled 242 Miles

Deer 255 is no ordinary mule deer. Her story, as it’s known to us, began in the spring of 2016. This is when researchers from the University of Wyoming first collared the doe while studying the state’s mule deer population in Wyoming’s Red Desert, located in the south-central portion of the state.

Mule deer populations throughout the West remain below target levels set by regional biologists. To try to understand more about these animals and what is causing their population to decline, researchers and biologists fit the deer with GPS tracking devices so they can observe movements remotely and learn more about where animals go and at what times of the year. They also collect information such as body measurements, whether a female is pregnant or not, how many fetuses she is carrying, and body condition.

Photos: Ben Kraushaar

Deer 255 was one of the deer that was collared from the Sublette Mule Deer Herd in the spring of 2016 but what happened next surprised everyone.

Early that summer, Deer 255 set out on a long-distance journey, traveling across Wyoming’s expansive sagebrush country and skirting the western edge of the imposing Wind River Mountain Range. Like most of her herd, she stopped over in the Hoback Basin for weeks that spring, but unlike the rest, she then kept migrating. When the doe finally reached her destination in Island Park, Idaho, just southwest of Yellowstone National Park, she had traveled roughly 242 miles, navigating busy highways, barbed-wire fences, and countless other hazards to complete her migration.

Then to the researchers’ dismay, Deer 255’s collar malfunctioned while she was on summer range in August, 2016. They had no news on the whereabouts of this exceptional ultra-long-distance migrator for all of 2017.

Thanks to the sharp eyes of a helicopter crew, researchers recaptured Deer 255 in the Red Desert in March 2018. This confirmed that Deer 255 hadn’t simply dispersed to a new range in Idaho. Instead, she ranges from the Red Desert to the Tetons, setting the record for the longest land migration ever recorded by a single mule deer!

What’s more, the story of Deer 255 didn’t end with a single incredible journey. From 2018-2020, the world champion doe has completed similar migrations, though she varied her summer range between Island Park, Idaho and Moran, Wyoming. And as of December 2020, Deer 255 was making her fall migration to the Red Desert with twin fawns!

You can learn more about Deer 255 and track stories of other Western migrations by following the Wyoming Migration Initiative on Facebook or visiting migrationinitiative.org.

Jackson Hole Wildlife Foundation

Being Wild Jackson Hole is an effort lead by the Jackson Hole Wildlife Foundation to help ensure survival of the wild spirit of this special place by embracing and promoting environmental stewardship, along with the values and actions that support it. We encourage visitors to learn about and participate fully in our conservation efforts.