The Hagfish is a primitive fish and a living fossil. She has a skull, but no vertebral column, she also lacks a jaw. Her teeth are keratin and situated in rows on her tongue, which she uses to rip pieces of rotting flesh from her carrion diet. This may include crawling inside the decaying corpse. She has the ability to digest organic matter with her skin. Her skin also contains numerous glands, from which she can exude copious amounts of mucus. This thickens upon contact with the water, becoming quite a deterrent to any predator that might wish to eat her. Research into this is also leading to a renewable alternative to petroleum.