The mule deer is big bodied in comparison to the Black tail deer. Also the muley has real big ears. Most of the black tail deer I have seen here in the west coast are brown in color, while the mule deer are grey. Mule deer do have eye guards, fact some have double eye guards on each side. The mule deer also has the big white rump that really sticks out when they are walking away from you. If you get a big black tail deer it will weigh around 130lbs, while mule deer get way up in the upper three hundred pounds. The antlers on muleys get a lot bigger then black tail deer.
This discussion about one side of the road has mule deer and the other side has black tail is laughable.