Asiatic Giant Salamanders and Hellbenders: Cryptobranchidae

Asiatic giant salamanders and hellbenders are the largest salamanders, and the largest amphibians. Amphibians (am-FIB-ee-uhns) are vertebrates (VER-teh-brehts), or animals with a backbone, that have moist, smooth skin; are cold-blooded, meaning their body temperature is the same as the temperature of their surroundings; and, in most instances, have a two-stage life cycle. Asiatic giant salamanders and hellbenders are born in the water and spend their entire lives there, never moving to land the way many other amphibians do. There are only three species in this group: Chinese giant salamanders, Japanese giant salamanders, and hellbenders. Asiatic giant salamanders grow to a length of almost 6 feet (1.8 meters) and weigh as much as 50 pounds (23 kilograms). The longest hellbender is about half that length. Asiatic giant salamanders and hellbenders have a broad, flat head and body that makes it easy for them to get under rocks. The tail is flat, too, but from side to side rather than from top to bottom, making it look like an eel's tail.

Asiatic giant salamanders and hellbenders have loose flaps of skin along the sides of their bodies and on the legs. This skin is filled with blood vessels only one cell thick that allow oxygen to pass directly from the water into the salamander's blood. This is how these salamanders breathe. They have lungs and go to the surface sometimes to gulp air but use the lungs mainly for staying stable in the water. The skin of these salamanders also makes lots of slime.

Asiatic giant salamanders and hellbenders have many colors and patterns. They can be gray, brown, greenish brown, yellowish brown, orange-red, or, rarely, white. Some of them have dark blotches or speckles. Japanese giant salamanders and Chinese salamanders have bumps on their heads and throats. The bumps on Japanese giant salamanders are large and separate from one another, but those on Chinese giant salamanders are small and paired.

The legs of Asiatic giant salamanders and hellbenders are thick and strong but short. The eyes are small and do not have eyelids. Hellbenders usually keep one pair of gill openings on each side of their head throughout life, but Asiatic giant salamanders lose these openings during metamorphosis, which can take as long as three years. Gills are organs for obtaining oxygen from water. Metamorphosis (MEH-tuh-MORE-feh-sis) is the process by which some animals change body form before becoming adults. The jaws of Asiatic giant salamanders and hellbenders are very flexible. Bundles of elastic tissue called cartilage (CAR-tih-lej) allow each side of the lower jaw bone to move by itself, so these salamanders can open their mouths very wide to suck in large prey.