> 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".
A table. My table. To solve this stupid riddle, I remove 2 of its legs before afternoon and screw one of them back on before the evening.
Sphinx, I dare you to refute me.