The New International Encyclopædia/Rattlesnake

RATTLESNAKE. An American venomous serpent of the family Viperidæ and subfamily Crotalinæ, distinguished from its congeners by a horny jointed appendage terminating the tail, the shaking of which causes a rattling noise likened to that of the ancient castanets or crotali. The Crotalinæ, until recently regarded as a family (Crotalidæ, ‘pit-vipers’), stand at the head of the ophidian ranks as the “most specialized type of snake structure,” and exhibit the “highest efficiency of the venom apparatus.” They are viper-like serpents of moderate length—none exceeding, and few approaching eight feet—but thick, heavy, and extremely muscular. They are viviparous, and mainly terrestrial; but one, at least (the moccasin), is decidedly aquatic, and several in Central and South America are arboreal. In colors they vary adaptively to their haunts. All are more or less distinctly marked with darker spots and patterns of squarish form. The group is predominantly American, but several species inhabit the East Indies, some of them belonging to the American genera Ancistrodon and Lachesis. The latter includes more than half of the 60 or so species of pit-vipers recognized, and is mainly Neotropical. Among its species are the large and dangerous bushmaster and fer de lance (qq.v.). Among smaller genera one is Teleuraspis, a species of which (Schlegelli) is arboreal and often winds around the stems at the centre of banana bunches, where it sometimes fatally bites the first man to handle the fruit. None of these have rattles. The true rattlesnakes, then, are only those pit-vipers which belong to the genera Sistrurus (three species) and Crotalus (15 species), all of which, except two species of Crotalus in South America, belong to the Northern Continent.

PATTERNS OF COLOR MARKINGS.

1, Common Eastern banded rattlesnake (Crotalus durissus); 2, Diamond rattlesnake (Crotalus adamanteus); 3, green rattlesnake (Crotalus lepidus); 4, plains rattler (Crotalus confluentus).

The curious epidermal structure at the end of the tail consists of a tapering series of amber-colored horny flattened bells which are locked into one another. The oldest or terminal bell (the ‘button’) is in reality the horny covering of the tip of the tail which was not discarded when the skin was first molted. At each succeeding molt the tip is pushed out by the new skin, and so a ‘bell’ is added at the base with each new shedding of the remainder of the skin. Theoretically these bells ought to indicate the number of moltings, and the age of the snake; but wear and accident interrupt or break the set so often that the rule does not hold with any certainty.

RATTLE OF A RATTLESNAKE.

1, Perfect rattle of a large banded rattlesnake; 2, longitudinal section of rattle; 3, separate segments of disjointed perfect rattle of Crotalus (side view): a, basal ‘joint’; b, button.

When the serpent is excited in any way it vibrates its tail, which (unless the creature is moving) is then held upright in the centre of the coiled body, with the head erect and menacing before it. This vibration—which is indulged by many kinds of snakes under nervous excitement—produces a peculiar humming noise, which increases in intensity and pitch as the snake's alarm or anger and the speed of vibration are augmented, until it may sound like the droning of an angry bee. The origin of the rattle can only be guessed at. A tendency toward armature of the tail is apparent in several other genera of pit-vipers; and in Sistrurus the rattle is much less well developed than in Crotalus. Apart from being a mere expression of emotion, the rattle serves to warn away cattle that might tread upon it, or enemies that might wish to seize it. This warning is well understood among all the wild animals, but when antelopes and deer hear it they will often attack the reptile and cut it to pieces with their sharp hoofs. The rattle is also believed to be a useful means of calling the sexes together.

The poison apparatus, fangs (which are of the proteroglyphic type), and the manner and result of biting, are treated of under Snake. Here it needs only be said that, like the vipers generally, these snakes are sluggish and loth to bite when it can be avoided, or when they are not surprised into a sudden stroke. This disposition varies, however, with the weather, their hunger, the season (all are irritable when sloughing their skin), and it differs in various species. Even the smallest may cause a man serious illness and perhaps death if it succeeds in introducing much poison into a wound; while a fairly delivered bite from the larger ones is almost certain to prove fatal. Its enemies are mainly confined to a few of the larger colubrine snakes, as the blacksnake, king-snake, and the like; to the pronghorn, Western deer, and Southern peccaries. Against man the rattlesnakes can make feeble resistance. Domestic pigs kill and eat as many as they can find, and rarely suffer harm, because of the thickness of the skin and the layers of fat underneath it, which prevent the fangs from entering or carrying venom to the system. Hunting of rattlesnakes affords occasional profit to a few persons, who find a market for their skins and for the clear smooth oil yielded by their fat, which is esteemed by watchmakers and gunsmiths, and is in demand as a medicine among the ignorant.

The most common and well-known of the rattlesnakes is that one (Crotalus durissus) formerly abundant all over the East, from the White Mountains in New Hampshire, and Lake Superior in the North, to the borders of the dry plains. It is larger in the Southern States than northward, and occasionally reaches a length of five feet, with a diameter in that case of four to five inches. The ground-color above varies from bright tawny to dark brown. A light line runs from the mouth to the eve, with a dark patch below; and the body is marked with three rows of confluent irregular brown spots, forming about 21 zigzag crossbars. The head is oval in outline. This snake inhabits wooded regions, avoiding prairies. It is especially fond of rocky districts, and hence is most numerous among mountains, where it is inclined to gather in considerable numbers in certain holes and caverns in the autumn, in order to undergo the winter sleep in closely entwined companies. About nine young are born annually in mid-summer. The Southern States have a still larger species known as the ‘diamond rattlesnake’ (Crotalus adamanteus) on account of the rhomboidal black blotches, each perfect in all its angles, and edged with yellow, which ornament its yellowish body. This snake sometimes reaches, on the Mangrove Islands of western Florida, a length of eight feet, and has so great a thickness that large individuals may be regarded as the most bulky of all venomous snakes, for the Oriental cobras, although sometimes longer, are far more slender. The range of the diamond rattlesnake extends along the coast from North Carolina to Texas, and a variety ranges westward to Lower California. Two other similar and almost equally large and dreadful snakes are Crotalus molossus and basiliscus. Southern California also has a remarkable species (Crotalus ruber), which has an oblong head, and whose markings are deep red or sometimes chestnut, upon a paler reddish ground. The rattlesnake of the plains (Crotalus confluentus) is a light-colored, obscurely marked, rather small species. It is highly variable in form and color, and is the kind constantly found in prairie-dog towns. Several other species occur in the Rocky Mountain region and Northern Mexico, one of which (Crotalus cerastes) is the characteristic snake of the deserts of the valleys of the Rio Colorado and Gila, where the people call it ‘sidewinder,’ from its habit of progressing sidewise instead of in the usual way. It takes its specific name from the fact that the plates above the eyes are thickened into hornlike cones, sometimes of considerable height. It is not of large size, but is dangerous because of the virulence of its poison.

The small, active prairie rattlesnakes, now greatly reduced in number, differ sufficiently from the genus Crotalus to be set apart into the genus Sistrurus. One of them (Sistrurus miliarius) is the ground-rattler of the Southern States, too frequently met with in stubble fields and grassy places. A Northern congener is the black rattlesnake or ‘massasauga,’ once common between the Alleghany Mountains and the plains, but now nearly exterminated except on the frontier. This species (Sistrurus catenatus) may reach a length of 30 inches, and is brown, with a series of darker brown transverse spots on the back, beneath each of which is a small brown spot forming a linear series along the sides. Its rattle is small, but can be heard at a considerable distance, and its bite is likely to be exceedingly troublesome to men and domestic animals, although not often fatal. These snakes prefer low, wet ground, the draining of which by the spread of farming operations has been the principal agency in their decrease.

Consult: Cope, Crocodilians, Lizards, and Snakes of North America (Washington, 1900); Stejneger, “Poisonous Reptiles of the United States,” in Annual Report United States National Museum for 1893 (Washington, 1895); Bumpus, Standard Natural History, vol. iii. (Boston, 1885); Stejneger, “Reptiles of Death Valley,” in North American Fauna, No. 7 (Agricultural Department, Washington, 1893). See Snake and Plate of Rattlesnakes.

RATTLESNAKES

1. COPPERHEAD (Ancistrodon contortrix).	4. GREEN RATTLESNAKE (Crotalus lepidus).
2. EASTERN BANDED RATTLESNAKE (Crotalus durissus).	5. PLAINS RATTLESNAKE (Crotalus confluentus).
3. DIAMOND RATTLESNAKE (Crotalus adamanteus).	6. HORNED RATTLER, or SIDEWINDER (Crotalus cerastes).