There was Man in his cozy little ramshackle hut still punished by the all mighty gods. And, there was Pandora frightened that the world will soon come to an end but she had hope. When the powerful gods punished Man they turned him into this small, intelligent creature that could jump higher, see clearer, and could swing on his tail and also swing with his strong arms.
But, the downside to this miraculous creature was that he had to forage for food and this creature could not interact with other of these creatures because he was the only one that was this species.
So then Zeus heard about this and he was elated that Man was being tortured. Hades also heard about His brother being elated that Man was being tortured so he wanted to get his brother furious so he turned Pandora into another one of these species. So then both of them were lonely and they made more of these species.
Zeus saw Man as pleased as can be so he tried to undo this but Hades had put an impossible reverse spell on both Man and Pandora. So Man was there with his lovely children. Poseidon called this species a Monkey because they hold the key to life.