Despite their curious name, “hellbenders” are not demons of the night but rather amphibious environmental monitors of Southeastern creeks and streams. Known to some old-timers as “walking catfish,” these super-sized salamanders gained the “hellbender” moniker for their freakish size and dark, moody color.

A mature hellbender is generally mud-green or grey-colored with dark splotches, weighs about four pounds, and has a flat, paddle-shaped body. Fleshy folds of skin that run the length of the salamander's side are one of the amphibian’s more interesting characteristics. These flaps increase the surface area of the hellbender’s skin to allow more oxygen into their lungs when submerged, which is basically all of their lives.

Hellbenders generally live in the area drained by the Ohio and Tennessee rivers. Very few have ever been found in watersheds that drain to the Atlantic, and none west of Arkansas.

The amphibians, which don’t start reproducing until age 7 and can live about 30 years in the wild, are found in the cool, rocky streams of the southern Appalachians. While Great Smoky Mountains National Park is probably the easiest place to fine one, you can get lucky at New River Gorge National River, Shenandoah National Park, or any other Appalachian park. In the Midwest, Ozark National Scenic Riverways is your best bet for spying one of these elusive creatures.

As much as two-and-a-half feet in length at adulthood, hellbenders feast on crawdads, small fish, and other invertebrates. Though most active at night, they will sometimes come out from underneath their rocks during an overcast day. The salamander, which has few natural predators other than birds, will hibernate to a degree during the winter, digging a nest in the mud.

Not much is known about the species' background. Some evidence inconclusively points to Chinese and Japanese salamanders as possible relatives. But Native Americans were known to eat the hellbender, so scientists are relatively certain that the species was not introduced from overseas. There are two subspecies, an Ozark Hellbender and an Eastern Hellbender, but some scientists have called for a review of this and are suggesting that the Ozark population isn't a subspecies. Instead, they believe the two populations are the same animal, but geographically and genetically isolated from each other

The enormous salamander's powerful tails, beady eyes, and broad head are perfectly adapted for the swift waters of the Appalachians. While it is not particularly venomous, the hellbender does secrete a slightly toxic slime to reduce friction and has a powerful jaw. Because of this, it gained a reputation among sportsmen as being a viscous fish killer that would ruin a good trout stream by gobbling down all the sport fish. Things were so bad that during the early 1900s a bounty was imposed on the critters, and the population – particularly in the Ozarks – is thought to have plummeted (based on how many are known to have been brought in for money).

Ironically, though, hellbenders are one of the best indicators of a healthy river, as they prefer to live in well-oxygenated, pristine waters. Starting around the 1970s, states began to list the salamander as threatened, but it has little widespread federal protection.

In a 1996 study in the Susquehanna River watershed, every hellbender caught and tagged was judged to be at least 25 years old. The scientists concluded that since the average age of the hellbender was high, there must be an incredibly low reproduction rate, which could mean significant species decline. However, scientists don't know for sure what the historic population levels were to begin with.

Threats to the salamander run the gamut of the usual river issues – siltation (having too much dirt in a river to the point that it's more mud than anything else), agricultural runoff, low dissolved oxygen levels, and dams all disturb the hellbender.

Conservation efforts over the past few years have done much in the eastern half of their range to restore the aquatic habitat that these remarkable animals need to survive. While the Ozark subspecies is thought to be bordering on extinction, the Eastern hellbenders of the Smokies and Blue Ridge mountains are on the upswing, thanks to increased protection, habitat restoration, and public education.

With hopes of bolstering the Ozark population, the St. Louis Zoo has partnered with the U.S. Fish and Wildlife Service's Mammoth Spring National Fish Hatchery in Arkansas to breed hellbenders for release into the wild, and the Missouri government has assembled a research team to compile a comprehensive study of the hellbenders.

Hellbenders are sometimes accidentally caught by anglers. If you happen to catch a hellbender, gently remove the hook and release it back into the water. You are encouraged to report any sighting of a hellbender to the nearest wildlife management agency, as population levels are only guesstimates. Moreover, if you see anyone harming a hellbender, you should report it to local law enforcement immediately.

Hopefully, with continued preservation efforts both in and out of our national parks, the hellbender will continue to cling to survival. While it isn’t likely to become a poster child for the parks (owing to its bizarre appearance), it is one of the park system's many treasures.