See! That catches animal! (5)
I believe the answer is:
lasso
'see that catches animal' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'see that catches animal' is the wordplay.
'see' becomes 'lo' ('lo' is an archaic exclamation meaning 'look!').
'that catches' means one lot of letters goes inside another.
'animal' becomes 'ass' (term for a donkey).
'lo' placed around 'ass' is 'LASSO'.
Can you help me to learn more?
(Other definitions for lasso that I've seen before include "Rope with 20" , "Looped rope used to catch cattle" , "One may be caught by this" , "A cowboy's rope with a running noose" , "Long rope with running noose" .)