Wild beast's jaw (3)
I believe the answer is:
yak
I believe this clue is a double definition.
'wild beast's' is the first definition.
(yaks are wild oxen)
'jaw' is the second definition.
(both can mean to talk excessively)
(Other definitions for yak that I've seen before include "Shaggy Tibetan ox" , "A Tibetan long-haired ox" , "A long-haired Asian ox" , "Himalayan bovine" , "Natter" .)