Reaching far back into the custard of my memory, I recall a book by (I think) R.M.Ballantyne, that fine writer of spiffing yarns, called The Gorilla Hunters which employed the same characters who had appeared in The Coral Island. In this yarn, which upheld all of the undoubted virtues of The British Empire, Gorillas were referred to, familiarly, as "puggies."
Any ideas where this word could have come from?