Animal all over mum (5)
I believe the answer is:
llama
'animal' is the definition.
(llamas are animals)
'all over mum' is the wordplay.
'over' says the letters should be written in reverse.
'mum' becomes 'ma' (both can mean mother).
'all' reversed gives 'lla'.
'lla'+'ma'='LLAMA'
(Other definitions for llama that I've seen before include "South American animal like the camel" , "A native of South America" , "Andean 'camel'" , "wool supplier" , "Load-carrier" .)