Cat rolling up in the early hours, awake (4)
I believe the answer is:
puma
'cat' is the definition.
(I know that puma is a type of wildcat)
'rolling up in the early hours awake' is the wordplay.
'rolling up' says the letters should be written backwards.
'in the early hours' becomes 'am' (short for ante meridiem).
'awake' becomes 'up' (similar in meaning).
'am'+'up'='amup'
'amup' backwards is 'PUMA'.
(Other definitions for puma that I've seen before include "Large American feline resembling a lion" , "Large American cat" , "South American cat" , "Large wild American feline" , "American wild cat" .)