Vehicle quickly does for tortoiseshell (8)
I believe the answer is:
carapace
'for tortoiseshell' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'vehicle quickly' is the wordplay.
'vehicle' becomes 'car' (car is a kind of vehicle).
'quickly' becomes 'apace' (synonyms).
'car'+'apace'='CARAPACE'
'does' acts as a link.
Can you help me to learn more?
(Other definitions for carapace that I've seen before include "Structure on back of tortoise or turtle" , "Hard shell of some animals" , "Crab's thick protective shield" , "Tortoise's upper shell" , "Hard thick shell of some creatures" .)