The Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis)
Cryptobranchus alleganiensis alleganiensis is the largest North American
salamander, ranging in length from 30.5 to 74 cm (Niering 1985). Eastern
Hellbenders are members of the order of tailed amphibians, Caudata and the
family, Cryptobranchidae. Along with C. a. bishopi, the Ozark Hellbender, it is
one of the two subspecies of hellbenders, also known as the Allegheny alligator
or devil-dog. C. a. alleganiensis is perennially aquatic, preferring clear
fast-moving rivers or large streams with rocky bottoms. Most are found in water
12 to 46 cm deep and tend to avoid areas with thick layers of silt (Hillis and
Bellis 1971). It ranges from the Susquehanna River and its tributaries in New
York and Pennsylvania to the Ohio River and its tributaries including the
Allegheny, which gives it its species name, westward to the Mississippi River
and southward to Missouri, Arkansas, and Georgia. It has also been recorded in
Iowa (Bishop 1943). C. a. alleganiensis has a dorsoventrally flattened body and
a laterally flattened tail. The tail is the main means of locomotion, but the
hellbender can also crawl when seeking refuge (Hillis and Bellis 1971). C. a.
alleganiensis is dark gray or olive-brown with a mottled or spotted pattern on
its dorsal surface. The ventral surface is a lighter shade with few markings (Niering
1985). The male and female are similar in appearance, but the male is broader
and heavier than a female of the same length. Eyelids are absent. It has five
toes on its hind feet and four on the fore feet, most of which develop during
the larval stage (Bishop 1943). C. a. alleganiensis is nocturnal, spending its
days hiding under rocks with only the tip of its broad head exposed. It exhibits
diurnal behavior only during its mating season which occurs in late summer or
early fall depending on geographic location. (Hillis and Bellis 1971). C. a.
alleganiensis practices external fertilization. The male will dig a
saucer-shaped nest-like cavity beneath a large, flat rock or sunken log. The
female lays 200-500 yellowish eggs in long strings. The male assumes a mating
position above or behind the female and sprays the eggs. The male will then
remain in the area to guard the nest (Niering 1985). Evidence has shown that the
male will eat some of these eggs and therefore may remain more to guard his food
supply than from a sense of parental responsibility (Hillis and Bellis 1971).
The larvae will latch two to three months later. The larva are approximately 30
mm long and born with gills which they will lose when they are 100-130 mm long
at about 18 months, leaving only a single pair of gill slits (Bishop 1943). The
hellbenders principle food source appears to be crayfish, this is most likely
for convenience since crayfish hide in similar locations as the hellbender. The
rest of its diet is composed mainly of other aquatic invertebrates such as
molluscs, worms, and insects. They have also been observed to eat small fish and
animal refuse (Hillis and Bellis 1971).

Bibliography



Bishop, S.C. 1943. Handbook of Salamanders. pp. 59-63. Comstock Publishing
Associates, Ithaca, NY. Hillis, R.E. and E.D. Bellis. 1971. Some aspects of the
ecology of the hellbender, Cryptobranchus alleganiensis alleganiensis, in a
Pennsylvania stream. Journal of Herpetology, 5:121-126. Niering, W.A. 1985.
National Audubon Society Nature Guides: Wetlands. pp. 384-385. Alfred A. Knopf,
Inc., New York, NY.