Muley Mystery

Photo by Mark Hengesbaugh 12/26/12
Mule deer (Odocoileus hemionus)

Photo by Mark Hengesbaugh 8/2010
Whitetail deer (Odocoileus virginianus)

Text also from Mark Hengesbaugh: 

At about 2,800 feet elevation, Sabino Canyon Recreation Area is desert mule deer habitat but nearly every deer we see there is a whitetail. What gives? We came across a mule deer on the Esperero Trail at the Forest Service corral, so I did some research. … 

In most of the U.S. West, if both species are present, mule deer occupy higher elevations and whitetails occupy lower elevations. But the situation is reversed here in the Southwest, where desert mule deer occupy lower elevations and the whitetail subspecies Coues are found higher, typically above 3,500 ft. 

David Lazaroff, author of Sabino Canyon: The Life of a Southwestern Oasis, said desert mule deer possibly have difficulty moving in and out of the rec area because: 

connections to similar desert habitat has been partly severed by intervening urban and suburban development. Whitetails seem to have a larger elevational range and so can move vertically in and out of the recreation area.

Easiest way to tell the difference between muley and whitetail: A muley’s tail tip will be black, not brown. More scientific: the metatarsal gland on the outside of the lower leg of a muley is a 3-6 inch oblong patch covered in tan hair (look where the barbed wire intersects the outside of the rear leg of the mule deer in the top photo). A whitetail’s metatarsal is below the mid-point of the lower leg, much smaller and circled in white hair (see the small, faint white circle of fur above the black dot lowdown on the outside rear leg of the whitetail.)