Travel, coming to stream, by which sits a wild animal (7)
I believe the answer is:
gorilla
'wild animal' is the definition.
'travel coming to stream by which sits a' is the wordplay.
'travel' becomes 'go' ('go' can be a synonym of 'travel').
'coming to' is a charade indicator (letters next to each other).
'stream' becomes 'rill' (rill is a kind of stream**).
'by which sits' is a charade indicator (letters next to each other).
'go'+'rill'+'a'='GORILLA'
(Other definitions for gorilla that I've seen before include "A large powerful African ape" , "Powerful great ape" , "Big ape" , "Chest-beating primate" , "brutal man" .)