I love these kinds of questions. The list of extant bipedal non-human animals is pretty short: kangaroos, some rodents, some birds, and at their highest speed, some cockroaches and reptiles.
But it was very common for theropod dinos. So why?
But it was very common for theropod dinos. So why?
Comments
Yeah, I guess all birds would be considered bipedal.
1. The bipedal common ancestor:
There's some evidence to suggest that the basal theropod was bipedal. Pelvis shape of all theropods seem well adapted to hip-support on hind legs. Quadruped dinos would then be an exception, not a rule.
The most bipedal specialists are the giant-headed predators like Allosaurus and T. rex. The jaw size of these animal is large in proportion to other body metrics. That requires counterbalance that would be difficult with four "points of force" as a center.
So, plant-eater = quad, meat-eater = biped.
3. Superior visibility
Kangaroos provide an interesting insight into bipedalism in mammals. They use less energy because of a "visceral piston" that returns most energy in hopping.
Then, of course, there's Option 4: They needed their hands free to operate the spacecraft controls, otherwise they wouldn't have been able to escape Chicxulub to colonize other planets.
I.. uh... try not to think about it too much.
https://youtu.be/PaVcpzYjdSs?si=7yBqLF5MXRKZXISb