Animal and large bird seen by river (5)
I believe the answer is:
lemur
'animal' is the definition.
(lemur is a kind of animal)
'large bird seen by river' is the wordplay.
'large' becomes 'l'.
'bird' becomes 'emu' (emu is a kind of bird).
'seen by' means one lot of letters go next to another.
'river' becomes 'r'.
'l'+'emu'+'r'='LEMUR'
'and' is the link.
(Other definitions for lemur that I've seen before include "Madagascan primate" , "Arboreal animal" , "Tree-living primate" , "Primate found only in Madagascar" , "Bushy-tailed primate" .)