> The only permanent bipeds of the animal kingdom alongside humans
Kangaroos?
replies(3):
Kangaroos?
What has 4 legs in the morning, 2 in the afternoon, and 3 in the evening?
The key here is how relaxed is the interpretation of "permanent".
~ https://en.wikipedia.org/wiki/Oedipus_Rex
( spoiler: he loved his mother )