Chatter ox (3)
I believe the answer is:
yak
I believe this is a double definition.
'chatter' is the first definition.
('yak' can be a synonym of 'chatter')
'ox' is the second definition.
(yak is a kind of ox)
(Other definitions for yak that I've seen before include "Pack animal" , "Natter" , "one sporting a thick coat" , "A long-haired Asian ox" , "Tibetan beast; chatter" .)