The
Sitka deer or
Sitka black-tailed deer (
Odocoileus hemionus sitkensis), is a subspecies of
mule deer (
Odocoileus hemionus), similar to the
Columbian black-tailed subspecies (
O. h. colombianus). Their name originates from
Sitka, Alaska, and it is not to be confused with the similarly named
sika deer. Weighing in on average between , Sitka deer are characteristically smaller than other subspecies of mule deer. Reddish-brown in the summer, their coats darken to a gray-brown in the winter. They are also good swimmers, and can occasionally be seen crossing deep channels between islands. Their average life span is about 10 years but a few are known to have attained an age of 15.