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' is an insertion indicator (inserted letters get eaten).
'animals' becomes 'camels' (I am not sure about this - if you are sure you should believe this answer much more).
'are' with its last letter taken off is 'ar'.
'ar' going within 'camels' is 'CARAMELS'.

Can you help me to learn more?