Mammalia
Cetartiodactyla (Artiodactyls)
Cervidae
Odocoileus
Odocoileus virginianus
white-tailed deer, whitetail
Live Animal
adult
F

Dark tail is common in some eastern varieties of whitetailed deer, as in this photo. Whitetailed deer in the Pacific Northwest do not normally have a black tail, so they are unlikely to be confused with blacktailed deer.
With Attribution
on photo, Arkive.org