Biped, or bi-pedal
You could walk and run
A biped has two legs used for walking, such as humans and birds.
Animals with two feet are "bipeds"
bipod biped (noun), or bipedal (adjective)
Having two feet like humans is called being bipedal. Some other animals that are bipedal are ostriches, kangaroos, birds, etc.
Quadrupedal means having four feet.
bi-pedal
Octopedal means having eight feet.
Centipede means "a hundred feet" which is close.
An animal having four feet is a quadruped which means four-footed or having four feet.
Scansion.
Human beings are described as bipedal, thus I believe the prefix is bi-.