Reindeer (7)
I believe the answer is:
caribou
'reindeer' is the definition.
(caribou is a type of reindeer)
This is all the clue.
(Other definitions for caribou that I've seen before include "North American reindeer" , "N. American reindeer" , "Ruminant" , "Arctic deer - a Rio cub (anag)" , "Arctic beast" .)