Jungle expert gutted zebra in lake (6)
I believe the answer is:
tarzan
'jungle expert' is the definition.
'gutted zebra in lake' is the wordplay.
'gutted' says to hollow out the word (remove centre letters) (to gut something is to remove its insides).
'in' is an insertion indicator.
'lake' becomes 'tarn' (tarn is a kind of lake**).
'zebra' with its middle taken out is 'za'.
'za' put within 'tarn' is 'TARZAN'.
(Other definitions for tarzan that I've seen before include "Apeman of fiction" , "Lord of the Jungle" , "Man raised by apes" , "Fiction's Lord of the Apes" , "Fictitious jungle hero" .)