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Research paper example essay prompt: Hellbender - 551 words
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Hellbender 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.
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