Little animals in sleeping quarters freeze (7)
I believe the answer is:
dormice
'little animals' is the definition.
(a dormouse is a little animal)
'sleeping quarters freeze' is the wordplay.
'sleeping quarters' becomes 'dorm' (dormitory).
'freeze' becomes 'ice' (as in water turning into ice).
'dorm'+'ice'='DORMICE'
'in' acts as a link.
(Other definitions for dormice that I've seen before include "Little hibernating rodents" , "Bushy-tailed rodents" , "creatures" , "Furry animals" , "Mammals" .)