Sweets are mostly eaten by animals (8)

'sweets' is the definition.
(caramel is a kind of sweet)

'are mostly eaten by animals' is the wordplay.
'mostly' means to remove the last letter (most but not all of the word).
'eaten by' indicates putting letters inside (inserted letters get eaten).
'animals' becomes 'camels' (I can't explain this - if you can you should give a lot more credence to this answer).
'are' with its final letter taken away is 'ar'.
'ar' inserted into 'camels' is 'CARAMELS'.

Can you help me to learn more?