The mule deer is a deer indigenous to western North America. The Mule Deer gets its name from its large mule-like ears. There are believed to be several subspecies, including the black-tailed deer. Unlike its cousin, the white-tailed deer, mule deer are generally more associated with the land west of the Missouri River, or more specifically, with the Rocky Mountain region of North America. Mule deer have also been introduced to Kauai (Hawaii) and Argentina. The most noticeable differences between whitetails and mule deer are the size of their ears, the color of their tails, and the configuration of their antlers. In many cases, body size is also a key difference. The mule deer's tail is black-tipped, whereas the whitetail's is not. Mule deer antlers are bifurcated; in other words, they "fork" as they grow, rather than branching from a single main beam, as is the case with whitetails. Each spring, after mating season, a buck's antlers start to regrow almost immediately after the old antlers are shed. Shedding typically takes place in mid February, with variations occurring by locale. Although capable of running, mule deer often prefer to stot, with all four feet coming down together.

Until recently, some taxonomists have attempted to separate white-tailed deer into a host of subspecies, based largely in morphological differences. Genetic studies, however, suggest that there are fewer subspecies within the animal's range, as compared to the 30 to 40 subspecies that some scientists described in the last century. The Florida Key deer, O. virginianus clavium, and the Columbian white-tailed deer, O. virginianus leucurus, are both listed as endangered under the U.S. Endangered Species Act. In the United States, the Virginia white-tail, O. virginianus virginianus, is among the most widespread subspecies. The White-tailed deer species has tremendous genetic variation and is adaptable to several environments. Several local deer populations, especially in the Southern States, are descended from white-tailed deer transplanted from various localities east of the Continental Divide. Some of these deer may have been from as far north as the Great Lakes region to as far west as Texas, yet are also quite at home in the Appalachian and Piedmont regions of the south. These deer over time have intermixed with the local indigenous deer populations.

Male white-tail in KansasCentral and South America have a complex number of white-tailed deer subspecies that

range from southern Mexico as far south as Peru. This list of subspecies of deer is more exhaustive than the list of North American subspecies, and the number of subspecies is also questionable. However, the white-tailed deer populations in these areas are difficult to study, due to over-hunting many parts and lack of protection. Some areas no longer carry deer, so it is difficult to assess the genetic difference of these animals.

This is where I found half of the infomation (http://en.wikipedia.org/wiki/White-tailed_deer)

This is where I found the other half of the infomation (http://en.wikipedia.org/wiki/Mule_deer)