The name “mule deer” comes from the animal's large-ear look. Mule deer are found throughout Montana, and have adapted well to sharing their habitat with people. In fact, it's not uncommon for “muleys” (as they're affectionately known) to "share" some peoples' backyard gardens.
Generally, mule deer are loners, only forming herds during the breeding season in late fall. If you're a spring hiker, you may stumble upon a fawn sleeping in a sheltered place. It might seem as though the fawn is abandoned, but the mother is always nearby. The fawn is just doing what it instinctively knows to do in the face of danger: hide.