As you can see, there is a lion behind Goku and Tranks.
There are a few guesses among the fans.
Why animal human were gone from the anime and comic books?
There are few rumors.
One of the rumors which is most famous, is the auther of Dragon Ball, Toriyama-sensei just forgot about animal human in his comic books.
Dragonball anime There were animal human in the comic book and anime in the beginning of the story.
Good post.