A movie of dogs climbing up and down stairs with two legs for some reason

Animals that walk quadrupedly basically use the four legs skillfully even in the stairs and move quickly, but there seems to be some dogs that move only with two legs in the world, and the appearance is contained in the movie It is.

Details are as below.
A dog rising quickly in front of the stairs and climbing the stairs.
YouTube - Bruno Walks up Stairs


This is a dog that steps down the stairs with only the front foot. It is quite acrobatic.
YouTube - Dog walks down stairs on 2 front feet


However, there are something above in the world, and some dogs get off the stairs without using their feet at all.
YouTube - Dog slides down stairs