Stupefaction overrode all ...

Stupefaction overrode all other emotion when I saw this creature on the lookout, lying in wait for the game. For it was an ape, a large-sized gorilla. It was in vain that I told myself I was losing my reason: I could entertain not the slightest doubt as to his species. But an encounter with a gorilla on the planet Soror was not the essential outlandishness of the situation. This for me lay in the fact that the ape was correctly dressed, like a man of our world, and above all that he wore his clothes in such an easy manner.
 Pierre Boulle

Quotes from the same author

But once an original book has been written - and no more than one or two appear in a century - men of letters imitate it, in other words, they copy it so that hundreds of thousands of books are published on exactly the same theme, with slightly different titles and modified phraseology. This should be able to be achieved by apes, who are essentially imitators, provided, of course, that they are able to make use of language.
 Pierre Boulle
There's always some further action to take.
 Pierre Boulle