Yes, the hippopotamus is the largest 4 legged animal.
anything with legs
An elephant is the largest mammal on land.
a snake
I am not sure what you mean but animal which walk on their hind legs have straight legs and they are called bipedalanimals.
no animal can walk backwards, they don't have legs!!
how about a water boatman
A fox is an animal that has 4 legs. It uses these to walk.
squealer
Most reptiles and amphibians that live in water can walk underwater. A number of other animals can walk underwater, including the hippo.
the blue whale (answer by karl )
a skunk can walk on it front two legs it uses it as a defense mecanism.
A animal with four legs Maybe a horse,dog or even a fish with four flippers something like that Carrie