Your informant at the zoo? (5,5)
I believe the answer is:
grass snake
'your' is the definition.
I can't tell whether this definition defines the answer.
'informant at the zoo?' is the wordplay.
'informant' becomes 'grass' (term for an informant or traitor).
'at the zoo?' becomes 'snake' (I can't justify this - if you can you should give a lot more credence to this answer).
'grass'+'snake'='GRASS SNAKE'
Can you help me to learn more?
(Another definition for grass snake that I've seen is " legless wild thing".)