This makes them very difficult to catch and to handle, but the slime is not poisonous. It quickly dropped the salamander with distaste. Hellbenders do have many, tiny teeth, but they usually don't try to bite. Unlike mudpuppies, hellbenders have external gills only as larvae. They lose the gills when they reach about 5 inches long, but retain gill slits through their entire lives.
Hellbenders are completely aquatic.
Only rarely have they been reported to come out of the water for any period of time. Since hellbenders spend their entire lives in water they need to have streams that are cool enough and which have enough oxygen to sustain them. In the Appalachian and Ozark Mountains in the eastern United States. Hellbenders range from southern New York south to Alabama and Mississippi, and west to Missouri and Arkansas. There are actually two subspecies of hellbenders.