The largest North American salamander, the Eastern Hellbender (Cryptobranchus alleganiensis) is a Maryland endangered species. The one to two-foot adult amphibians can still be found in Maryland's Garrett County. Habitat degradation from increased sedimentation and other water contaminants have resulted in this environmentally sensitive species no longer being found in central and eastern Maryland.
Fast moving, clean streams are the ideal habitat for the aquatic Eastern Hellbender. They swim with their flat tails and respirate through their skin, which is very slimy. Capillaries in folds of skin along the sides between the front and rear legs exchange oxygen and carbon dioxide with the aquatic environment; a property that has also made them exceedingly sensitive to pollutants in the water.
The usually brownish or gray large salamanders mainly feed on other aquatic life including crayfish and fish, with most feeding activity occurring in the first several hours after dark. Poor eyesight for hunting is made up for by sensitive smell and the ability to detect vibrations in the water. Hellbenders are known to be solitary, with single animals covering a territory and excluding other encroaching hellbenders.
Mating occurs mainly in the September-October period. Males will carve out a depression in the stream bottom under the structure of a rock or log, with an entrance usually facing downstream. A female will enter the depression, and over two to three days lay up to 200 eggs in strings similar to other amphibians, with the male fertilizing the eggs externally.
The female is then driven out of the nest, with the male guarding and circulating water around the egg mass to assure an oxygen supply. Males have been known to attract other females to repeat the egg-laying, accumulating a larger egg mass. The males have also been observed cannibalizing the fertilized eggs. In about two months, the larvae, an inch in length at hatch, have gills that disappear after the limbs appear at about 4 to 5 inches in length.
An interesting characteristic of the Eastern Hellbender is its light sensitive cells in its skin, including many in its tail. Since hellbenders are preyed upon by fish, snakes, and turtles, it is thought that the light sensitivity of the skin, especially in the tail, makes it easier for the large creature to ensure that it is completely hidden under rocks or other structure in the stream.
Eastern Hellbender habitat reduction similar to that in Maryland has occurred in other states, with state-threatened and endangered species protections in Ohio, Illinois, and Indiana and proposals in other states. The Eastern Hellbender is also proposed for Federal protections, as populations across its range have declined since 1980 by over 40%. The Eastern Hellbender's current range is mainly in mountainous areas from New York to the Tennessee River basin of Georgia and Alabama and west to parts of the Ohio and Missouri River basins.
Article by Tom Anderson, FCFCDB Member
Nature Note for 1/20/2019