Sea creature -- sound of body following rear of dhow (5)
I believe the answer is:
whale
'sea creature' is the definition.
(creature of the sea)
'sound of body following rear of dhow' is the wordplay.
'sound of body' becomes 'hale' (I've seen this in another clue).
'following' means one lot of letters go next to another.
'rear of' suggests the final letters.
The last letter of 'dhow' is 'w'.
'hale' put after 'w' is 'WHALE'.
(Other definitions for whale that I've seen before include "Maybe humpback" , "Large marine creature" , "It breathes through a blowhole" , "Large cetacean" , "Mammoth marine mammal" .)