Species of Rattlesnake.— Of rattlesnakes three species of Sistrurus and 16 of Crotalus have been described, three of which are South and Central and the rest North American. None occurs in the West Indies. The species of Si-s trurus are small snakes with the snout and frontal region of the head covered with large plates. The ground rattlesnake or massasauga (S. catenatus) is found on low prairie lands from Ohio and Minnesota southward, but is now rare or exterminated in all settled parts. It reaches a length of three feet and is not con sidered especially dangerous. About six young are born alive in September; and this is one of the snakes for which it is pretty clearly established that the newly-hatched young seek refuge from danger in the mouth and gullet of the mother. A related species (S. miliarius) is found in the Southern States.
In the genus Crotalus the entire top of the head is covered with small scales. The com mon or banded rattlesnake (C. horridus) was formerly abundant throughout the entire eastern United States and it is the only species found in southern New England and the Middle States, but has been largely exterminated by the white man and his companion, the hog. The latter in roaming the woods in search of mast, etc., never fails to kill and devour the rattle snake whenever possible. It is commonly be lieved that the hog is immune to snake-bites, but the truth is that the poison is. dissipated in the thick skin and layer of subcutaneous fat and miter reaches the vascular tissues beneath. This rattlesnake prefers sparsely wooded rocky ridges with sunny exposures and in such locah lies is stilt common in the mountains from Pennsylvania to Tennessee. It is a sluggish and generally peaceful creature, and seldom bites except to secure food, unless it be trod upbn or startled, When about .to strike it coils with the head in the middle and elevated • and the rattle sounding, delivers a lightning-like blow and immediately recoils or slowly retreats. It seldom attacks without provocation or follows a foe. All kinds of small mammals, especially mice> and occasionally birds, are its . food, and it drinks water freely. The cold months of the year are passed in hibernation and frequently large numbers of these snakes congregate in caves or beneath rocks for this purpose. Mat ing takes place in the early summer and about September from six to nine young about nine inches long are born alive. A length of five feet is sometimes attained, but ordinary examples seldom exceed four. Among the natural ene mies of the rattlesnake are the kingsnake and blacksnake, birds of prey and herons. The diamond or water rattlesnake (C. adamanteus) reaches a length of more than eight feet and a circumference of 15 inches and is not only the largest of the rattlesnakes, but the bulkiest of all poisonous snakes, being exceeded in length only by the slender snake-eating cobra.
It inhabits the Southern States and is particu larly abundant on the Florida Keys. Except that it prefers the vicinity of water, in which it swims freely, its habits are much like those of the common species. Because of its great size, and the large amount of venom that it secretes, this is an extremely dangerous reptile; it is also sometimes inclined to be aggressive. The prairie rattlesnake (C. confluentus) inhabits most parts of the Western plains and deserts and is exceedingly abundant in unsettled re gions. This is the species which plays a part in the famous triple alliance of prairie-dog, owl and rattlesnake, which, although popularly sup posed to be a most amicable arrangement, is at best a state of armed neutrality and frequently of open warfare. The owls and snakes seek the burrows of the marmot as safe retreats and nesting sites, as well as for the purpose of feed ing on the young marmots, while the latter fre quently show their resentment of the intrusion in a variety of ways. A very distinct species is the horned rattlesnake (C. cerastes), in which the superciliary scales are produced into a pair of prominent horns surmounting the eyes. It is abundant in the desert region of the South west, especially about Death Valley, and is known in Arizona as °sidewinder" from its peculiar habit of retreating sidewise from an in truder. Several other species inhabit these hot dry regions.
Service to Man.— Rattlesnakes possess a certain economic importance. As checks on the increase of the native mice and rats, they, in common with many other snakes, perform an important service. Their venomous qualities are such a menace man and beast as to render their destruction both expedient and certain in all thickly settled districts. By the Indians and by the whites in certain parts of the South their flesh is relished; an oil or salve; supposed by the credulous to possess peculiar medicinal virtues, is claimed to be manufactured from their livers and other fatty parts; and the use of the skin for making purses, belts and other small arti cles is well known. Certain tribes of Indians employ these snakes in their ceremonials and others formerly poisoned the tips of their war arrows with rattlesnake vy-nota, while the rat ties always figured among the charms of the medicine-man.
Bibliography.— Cope U. S. Na tional Museum for 188' ; Stejneger, The Poisonous Snakes of North America' (1893) ; Mitchell and Reichert, Resei rch es Upon the Venom of Poisonous Serpents' (Washington 1886) ; Ingersoll, (Country Cousins> (New York 1885).