Quite a few sleep at the poles (6)
I believe the answer is:
dozens
'quite a few' is the definition.
(I've seen this in another clue)
'sleep at the poles' is the wordplay.
'sleep' becomes 'doze' (doze means to sleep).
'at' is a charade indicator (letters next to each other).
'the poles' becomes 'ns' (north and south poles).
'doze'+'ns'='DOZENS'
(Other definitions for dozens that I've seen before include "Sets of twelve" , "Large numbers" .)