Hellbender Essay, Research Paper
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).
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.