Egg-laying mammal can hide when disturbed (7)
I believe the answer is:
echidna
'egg-laying mammal' is the definition.
(echidna is a kind of egg-laying mammal)
'can hide when disturbed' is the wordplay.
'when disturbed' is an anagram indicator.
'can'+'hide'='canhide'
'canhide' is an anagram of 'ECHIDNA'.
(Other definitions for echidna that I've seen before include "Prickly creature" , "Little animal" , "Creature with spines" , "Such a beast" , "Australian creature" .)