**Description:** The largest salamander in North America; features a flat head, tiny eyes, and loose, wrinkled, "slimy" skin.
**Size & Weight:** Can grow up to 29 inches long and weigh over 5 lbs.
**Sexual Dimorphism:** Males develop a circular "swelling" on the chin during breeding season.
**Habitat:** Require fast-flowing, clean rivers with large, flat rocks for hiding.
**Behavior:** Breathes primarily through its wrinkled skin; they are a vital "bio-indicator" of clean water.