Why do you make the Bracha Mishaneh Habriyos on seeing a monkey?
The Mileches Shlomo on Kilayim (8:6) says the gemara in Sanhedrin says that the Dor HaMabul (generation of the flood) turned into monkeys and that is one of the reasons we make the bracha Mishaneh Habriyos translated- who changes the creations-on monkeys.
The straightforward answer is that (at least in Talmudic times, to someone who had never seen them before), elephants and monkeys just struck people as so amazingly different, that a religious person's reaction would be:
Blessed are you God, King of the World, who makes such variety in creations!
Note that these are two of the most-intelligent animals on the earth's surface. (Let's leave dolphins out of this.) Rambam (Hilchos Eruvin 6:22) even writes about a trained monkey or elephant delivering a package. I always wondered whether the intelligence factor had something to do with their notability (and hence the bracha).