Sound like a bear and sound like a horse? (6)
I believe the answer is:
whinny
'sound like a horse?' is the definition.
(a whinny is a high-pitched neigh)
'sound like a bear' is the wordplay.
'sound like' shows a homophone (sound like).
'a bear' becomes 'Winnie' (Winnie the Pooh is a fictional bear).
'winnie' is a homophone of 'WHINNY'.
'and' is the link.
(Other definitions for whinny that I've seen before include "Gentle or joyful neigh" , "Animal's sound" , "Horse's cry" , "animal noise?" , "Beastly sound" .)