Had read some midrash or zohar that some apes were human beings who were banished and became apes. Don't remember the source. Does anyone know this?
Masheches Sanhedrin 109 mentions this idea. The Mishna said that the dor haflaga has no share in the world to come. The gemara asks what they did, and says they built a tower. Rav Yermiya bar Elazar says there were three groups:
Some wanted to live in the heavens, so Hashem scattered this group.
Others wanted to serve avoda zarah, so Hashem mixed their languages up.
The last group wanted to fight Hashem, so Hashem turned them into monkeys, ruchot (spirits), and sheidim.
On page 145 of "Call of the Torah" by Rabbi Elie Munk, he says, quoting the Sefer Divrei Yirmehayu, "Tradition tells us that the tower-builders suffered three punishments. The Semites, who wished to perpetuate the memory of the Flood's victims with a memorial, were scattered over the earth--the lesson of the Flood should have been taught to the living and not commemorated in stone. The Hamites, who intended to wage war with God, were banished and 'were transformed into monkeys and demons' (Sanhedrin 109a), the image of their degeneration and decadence. As for the offspring of Japheth, who had wanted to erect a gigantic temple to their idols--their common language, the mainstay of their collective strength, was taken from them."