Bears are mammals that live in woods and mountains. In "Thar Be Dwarves", Bears Yogi and Boo Boo make a cameo where they try to steal Billy's picnic basket. Billy escaped from The Bears by running into a cave. The Bears couldn't follow because, according to Yogi, "Bears are terribly afraid of caves".
In "Big Boogey Adventure", Horrors Hand revealed that Irwin's worst fear is telling jokes to bears, so he was immediately put on a stage, holding a microphone, in front of a crowd of grizzly bears.