Mammal related to the giraffe (5)
I believe the answer is:
okapi
'mammal related to the giraffe' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for okapi that I've seen before include "Giraffe-like animal with stripes" , "Type of giraffe" , "Hoofed mammal" , "Small giraffe" , "Native of Central Africa" .)