There are two species of hellbenders in the United States. The Eastern Hellbender (Cryptobranchus alleganiensis) can be found in much of the Appalachian mountains. The Ozark Hellbender (Cryptobranchus alleganiensis bishopi) is a subspecies of the Eastern Hellbender. Its range is considerably smaller, and can be found only in southern Missouri and Northern Arkansas in the White River watershed. Although populations of Eastern Hellbenders are declining, their conservation status remains ‘threatened.’ Ozark Hellbenders, on the other hand, are endangered species in each of the states in which they occur.
Adult Eastern Hellbender
Hellbenders are entirely aquatic salamander species that is long-lived. In general, adults can reach lengths of up to 2.5 feet and weigh upwards of five pounds. They have very large, flattened heads with beady eyes. Their bodies are long and have many folds of skin, giving the hellbenders a greater surface area to uptake oxygen (which occurs only through the skin). Ozark Hellbenders and Eastern Hellbenders appear very similar to one another, and can usually be distinguished only by the coloration of the chin. Their primary diet is crayfish, but are known to eat small aquatic vertebrates. Like many other long-lived species, they tend to reproduce more slowly (reaching sexual maturity by around age 6) which makes each reproductive adult in the population extremely important.
Causes of Hellbender Declines
The causes for the decline of Ozark Hellbenders are similar to those causing declines of other amphibian species worldwide. Perhaps the most important for this species is deteriorating stream quality. Ozark Hellbenders require clean, clear, shallow water in order to live and reproduce. Increased siltation caused by gravel mining and erosion from urbanization and agriculture cause physical harm to the hellbenders. Damming of streams has also made them deeper and eliminates hellbender habitat. Runoff from pesticides may also pose a problem for hellbenders by reducing sperm counts, altering behavior, and diminishing water quality. Overcollection by hobbyists and infection by the chytrid fungus have also been cited as potential reasons for population declines.
Ideal Hellbender Habitat
Because these animals are cryptic and hard to find, there are few data regarding their past numbers which makes it difficult to determine the extent of their population declines. It is also difficult to breed these animals in captivity, so captive breeding programs will not likely help this species. Fortunately, conservation efforts have been stepped up to more closely monitor Ozark Hellbender populations and to discover and eliminate the causes of declines of Ozark Hellbenders.