It was hard to believe he could run on four legs.

A character that looked like a house running on four legs.

He was running on three legs and holding me in the fourth.

They had learned how to deal with predators that ran on two legs or four.

I was much smaller, and ran behind human beings on four legs.

Via the process of natural selection, one species developed the ability to run on two legs.

They ran on two legs, holding their tail and head in a horizontal position.

They can even run on their hind legs for short distances.

Then it howled and charged at them, running on two legs.

"We do have someone who can run on four legs," Taran said suddenly.