Tyrus created these when he saw two Dwarf twins mapping the Underdark. He watched them carefully, and was amused in their slap-stick sense of humor and dislike towards life besides their own. He played a prank on them, by replacing their canteens with a magic potion that caused them to become hunchbacked and grow hair all over their bodies, making them appear like bears.
They can be heard from the light yelping noises they make to communicate. Rumors say that they can comprehend common, but can not speak it. Tyrus cursed the Gnolls to an extended life, twice as long as Humans and gave them the ability to see in the Underdark he sent them out to explore the caverns.