What's Hurting Our Hellbenders?

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Published on: Jun. 2, 2004

Last revision: Nov. 16, 2010


The eastern hellbender (Cryptographs alleganiensis alleganiensis) and the Ozark hellbender (C.a. bishopi) are harmless animals that inhabit Missouri's cold, fast-flowing streams. Once plentiful, their populations are now in peril, and the Missouri Department of Conservation is trying to find out why.

Between 1971 and 1973, researchers observed more than 1,000 hellbenders in the Niangua River. By the 1990s, however, the population had declined by 80 percent. Hellbender numbers in the Big Piney, Gasconade, Eleven Point and North Fork rivers showed similar decreases. Overall, hellbender populations declined by an average of 77 percent.

Equally disturbing is the discovery of many hellbenders with deformities, including missing or malformed legs.

In Missouri, hellbenders can grow up to 2 feet long. People have described them as something only a mother could love. They are reddish-brown and blotchy in color, with wide, flat heads, tiny eyes, short legs, loose skin and a very slimy film over their entire body. The film is a protective coating that decreases friction while swimming. It also is a mild skin irritant to those who come into contact with it.

Hellbenders mostly eat crayfish. They are mainly nocturnal and are seldom encountered. Anglers may catch them on hook and line, however, and giggers might spot them at night with the aid of a light.

Their wide, flat heads make it easy for hellbenders to slip under large, flat rocks on the bottom of fast-moving streams. They usually remain within a home range of less than 70 square yards.

During breeding season in September and early October, female hellbenders deposit between 200 and 700 eggs in a clump. All the eggs are attached by a single strand, however, so their egg masses resemble a bunched string of pearls. After being externally fertilized by male hellbenders, the eggs hatch within four to six weeks. The males remain during this time to guard them.

When the eggs hatch, the larvae that emerge are less than an inch long. During the larval stage, the animals breathe through feathery gills on the side of their head. The larval stage lasts for about two years, during which time a larval hellbender grows to four or five inches long.

At this stage, hellbenders reabsorb their feathery gills and breathe through the many folds of their loose skin. They don't reach sexual maturity until they are about 14 to 15 inches long, which usually takes from five to eight

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