Hellbenders are large aquatic salamanders. They have a wide, flat head with tiny eyes and a broad and vertically compressed, rudderlike tail. The body and legs are covered with prominent folds of skin. A hellbender's coloration is a combination of browns or grayish browns. Some dark markings occur on the back and tail, but they lack a distinct pattern. The belly is yellowish brown. During breeding season (late summer and early autumn), they may have an overall reddish brown color.
Two subspecies of hellbenders occur in Missouri. The eastern hellbender (Cryptobranchus alleganiensis alleganiensis) occurs in several eastern states, from New York to Georgia and Missouri, while the Ozark hellbender (C. a. bishopi) lives in the Ozarks of southern Missouri and northern Arkansas. The Ozark hellbender has black or dusky markings over a large part of the chin, while the eastern hellbender usually lacks such markings. Also, the Ozark hellbender has more dark brown markings on the back, is smaller, and weighs less.
Similar species: Mudpuppies (Necturus spp.) have external gills, which are red and plumelike, behind the head on both sides. They have 4 toes on each foot. As adults, mudpuppies reach only 8–13 inches in length. Hellbenders lose their external gills once they reach 4 or 5 inches long, they have 4 toes on the forelimbs and 5 toes on the hind limbs, and their total length may reach 24 inches.
Length: 11–20 inches.
Missouri is the only state to hold both subspecies of hellbenders. The eastern hellbender subspecies is found in the northern and central Ozarks, in rivers feeding the Missouri and Meramec drainages. The Ozark subspecies lives in south-central Missouri, in the White River system.
Habitat and Conservation
Hellbenders are fully aquatic and live under flat rocks in large, permanent streams and rivers. Since the 1970s populations have declined drastically. Most are older adults. Some have limb deformities. The lack of young spells trouble for hellbenders, which are listed as rare, threatened, or endangered nearly everywhere they are found.
In 2011 the Ozark subspecies was listed as endangered under the federal Endangered Species Act.
In 2021, Missouri's distinct population of the eastern hellbender subspecies was listed as endangered under the federal Endangered Species Act.
Hellbenders need clean, clear, cool rivers to survive, and they should never be harmed or removed from the wild.
Hellbenders eat a variety of aquatic prey, such as small fish and insects, but around 90 percent of their diet consists of crayfish. Despite numerous studies, fish eggs have never been found in the stomach of a hellbender — they do not harm populations of game fish.
Both subspecies of hellbenders that occur in Missouri are listed as endangered by both the state of Missouri and by the federal government. They may become extinct in our state in less than 20 years. None may be taken from the wild for any use.
- The Ozark hellbender subspecies occurs only in the White River system in southern Missouri and northern Arkansas. Its population has decreased about 75 percent since the 1980s.
- Missouri's distinct population of the eastern hellbender subspecies occurs is limited watersheds in our state and has declined drastically.
Challenges leading to the decline of these native salamanders include habitat loss, sedimentation, lowered water quality, illegal collection, habitat disturbance (as when people move or dislodge river rocks and kill the animals hiding below), small populations, population fragmentation, increased numbers of predators, and disease.
These fully aquatic salamanders take in oxygen through their skin. By day, they hide under large flat rocks; by night, they walk slowly along the stream bottom, hunting. Breeding takes place in late summer and early autumn. Females may not breed until they are 7–8 years old and may only breed every 2–3 years. Fertilization is external, 200–700 eggs can be produced, and the males guard the eggs. Under natural conditions, hellbenders can live 30–35 years. One specimen reached age 55.
Hellbenders are a major indicator of the overall health of a river or stream. If there is something in the water causing their numbers to decline, it can affect other species as well, including us.
In 2019, the hellbender was designated as the official endangered species for the state of Missouri. At the time that legislation passed, Missouri had 70 species of plants and animals listed as state-endangered, 27 species on the federal endangered list, 15 species on the federal threatened list, and 1 species being considered as a candidate for federal listing.
A number of organizations, including MDC, are partnering with the Saint Louis Zoo in a captive breeding program for hellbenders, with the aim of reintroducing them into the wild.
Hellbenders are part of a healthy natural aquatic environment, and they play an important role in maintaining crayfish populations.
Hellbenders have been on our continent for more than 6 million years and are a unique part of our wildlife heritage.