Mammals
Mule Deer
Odocoileus hemionus · also called mule deer
Startled on a steep, rocky slope, a mule deer bursts into a stiff-legged bound, all four feet leaving the ground at once in a distinctive gait perfectly suited to the broken mountain terrain it prefers over open, level ground.
Overview
The mule deer, Odocoileus hemionus, is a large, mountain-adapted herbivore native to mountain, grassland, and desert habitat across a broad range of western North America. Its distinctive stotting gait, mule-like ears, and stronger preference for rugged terrain compared with the white-tailed deer make it one of the more physically and behaviourally distinctive large mammals found across the American West.
Built for the mountains, not the plains
While its close relative the white-tailed deer thrives on flatter agricultural and forest-edge land, the mule deer has instead specialised for rugged, broken terrain, using a bouncing gait and seasonal elevation migrations well suited to life in the mountains.
Status
Least Concern but decreasing, widespread across suitable mountain, grassland, and desert habitat throughout western North America, with declines linked to habitat loss and disrupted migration corridors.
Mule Deer: common questions
Why is it called the mule deer?
This species has unusually large ears relative to its head, a feature reminiscent of a mule's ears, which gave rise to its common name and remains one of the more immediately noticeable features distinguishing it from other North American deer species.
What is stotting, and why does the mule deer do it?
Stotting is a distinctive stiff-legged bounding gait in which this species launches all four feet off the ground simultaneously, an efficient and surprisingly fast way to cover the rugged, broken terrain it favours, quite different from the smoother running style of the white-tailed deer.
How can you tell mule deer and white-tailed deer antlers apart?
A male mule deer grows antlers that branch into roughly equal forks rather than growing from a single main beam the way a white-tailed deer's antlers typically do, making antler branching pattern one of the more reliable ways to distinguish the two similarly sized species.
Why do mule deer migrate between different elevations?
This species often moves between higher-elevation summer range and lower-elevation winter range to track more favourable food availability and avoid the harshest winter conditions found at higher elevations, a seasonal migration pattern that some populations have followed along the same routes for generations.