What person was the muppet character "Animal" modeled after?

It is thought that the character was modeled after Keith Moon, drummer from The Who. However, the designers insist that "Animal" was not based on anyone specific.

http://muppet.wikia.com/wiki/Animal

Another take on it:

Animal is sometimes referred to as, "The little skirt chaser." He was actually influenced by someone that was known by Jim Henson who would get drunk and chase after women. Animal's famous way of saying, "Woomaaan!" was actually influenced by this real life person. That person was the drummer for the group The Who, Keith Moon.

http://sumonova.com/animal-muppets-crazy-stuff-animal-facts-about-everyones-favorite-muppet-drummer/