Various small, ground-keeping snakes lead to another conspicuous American group, the racers and black snakes of the genera Spilotes and Zamenis, of which species and near relatives are numerous in Europe and Asia, a Malayan example growing to a length of ten or more feet—probably the longest of colubrines. Three different "black snakes" are known among us. The largest is the "gopher snake" or "indigo snake" of the sandy parts of the southeastern States, which may approach eight feet in length, and it is a variety of the still larger yellow "rat snake" or "cribo" of the tropics, which is protected about villages and houses as a good-natured exterminator of vermin. Our variety has a useful breadth of taste and lack of choler, and its haste to escape into a gopher turtle's hole when a man appears gives it one of its names, while its glossy, blue-black color, relieved only by a reddish chin and throat, accounts for the other. They are real pets, showing no fear and offering no harm; the closely related "rat snakes" of India, on the other hand, although similarly protected as ratters, are described as diabolical in temper, and thus usually remain untamable. To some extent in the South, but principally in the Northern States east of the plains, the commonest black snake is the "black racer," which west of the Mississippi, instead of being pure satiny black, with white chin and throat, appears in a bluish green hue, often with yellowish belly, and is known as "blue racer." Third, we have the less numerous and larger "pilot," whose scales are noticeably keeled and have each a touch of white. Raymond L. Ditmars takes great pains to relieve these snakes of various calumnies, as that they hunt for rattlesnakes and copperheads (whence the name "pilot"), as that they "constrict" their prey, as that they "fascinate" anything, and as that they maliciously attack human beings—on the contrary, they make frantic efforts to get away the instant their fears are aroused, and few things on earth can make better speed than this black rocket. If cornered, however, it will turn on the enemy, rear a third or more of its length, and strike repeatedly with a force and rapidity hard to avoid. Yet both the common and the indigo species quickly become docile and show signs of recognition and partiality toward their human friends. The long, slender "coachwhip snake" of the South and the equally thin and swift striped "racer" of the Pacific coast are allied species.
The genus Coluber, to which belongs the famous Æsculap snake of central Europe, is represented among us by a series of large and gayly colored species. One is the yellowish, brown-blotched fox snake of the prairie States, which is a ground keeper and a great hunter. In search of rats and mice it often haunts haystacks and barns where it should be welcome. "One snake is worth a dozen traps, for the reptile prowls into the burrows and nests of rats and mice and eats the entire brood." Similar in size (six feet) and habits is the brilliant red-and-crimson corn snake of the Southern States, which is a great mouser and also an agile climber after nests of birds, whose eggs and young it likes. Another, even larger, coluber of the South is the four-striped chicken snake, useful in its pursuit of small rodents, but, like the pilot black snake, with too great a fondness for hen's eggs and young poultry to be liked by farmers.
The big, gray, blustering "bull snakes" of the southern and western parts of the Union take their name from their habit of emitting a loud and prolonged hiss when annoyed. They keep on, and under, the ground in sandy regions, feed on small mammals and birds, and are powerful constrictors; they are also noted for morose and savage dispositions. Next to these repulsive reptiles come in classification the beautiful and gentle green snakes—slender little creatures that hunt for caterpillars and various insects through the foliage of bushes, among which their gracefully festooned length is hardly visible. South America has another group of very long and slender insect eaters and nest robbers known as "tree snakes," whose habits are similar but on a larger scale, and which have a wonderful power of riding securely on the branches, no matter how violently they are waved by the wind.
Passing over a number of small, smooth-scaled serpents, of which the pretty ringneck is an example, we come to the important genus Ophiobolus, which contains the king snakes, milk or house snakes, coral snakes and others, represented in the Old World by the genus Coronella. They vary in size from fourteen inches to six feet, and in color from gray with dark blotches to a ringed pattern of red, black, and yellow, often of brilliant beauty; but there is much individual variation.
The king snake might easily furnish material for a long chapter. Its name follows from its known disposition to pick a quarrel and fight with any serpent it meets, big or little; and quite independent of whether it is hungry, for it is as fond of eating its own kind as it is of lizards, toads, mice, birds and anything else that comes in its way on the ground, for it is not much of a climber. Our books are full of incidents of its destruction of poisonous species, and the popular belief is that it hunts for, and relentlessly pursues rattlesnakes, copperheads, etc., but the authorities assure us this is not so. If it accidentally encounters a rattler or moccasin, it kills, and perhaps eats it; but it does the same with any other serpent. It is an exceedingly quick and powerful constrictor, and careless of bites, for it is entirely immune to venom. Captive specimens have been repeatedly hypodermically injected with the poison of all sorts of American venomous serpents, as well as bitten by them, and have shown little if any effect. But wounds enrage it. Winding its lithe body round and round the doomed creature, until every part of the shining length is engaged, it tightens with such strength that the victim is benumbed, unable to bite and quickly strangled. Nevertheless these snakes submit easily to confinement and speedily grow perfectly gentle and friendly.
The common northern representative of the genus is the house snake or milk snake—names given to several other species; it is also known as "checkered adder," because of the general resemblance of its blotched form to the dreaded copperhead. It is gray above, with a series of large, chestnut-brown saddles on the back, smaller blotches alternating with them along the sides; the belly is white, marked boldly with square black blotches. The pattern and tints vary widely. This snake is a lover of warmth and a hunter of mice and rats, wild and domestic; and in search of them it frequents pastures and damp meadows, where such wild game abounds, comes much about stables and houses, and often creeps into the rural dairies that are usually close to springs. Serpents with these inquisitive habits are familiar in all parts of the world, and from time immemorial have been accused, among other iniquities, of milking cows and goats, and of drinking and spoiling milk and cream on the shelves in dairies and cellars. These beliefs survive among country people to this day, as I found out a few years ago by an extensive correspondence of inquiry, in which incredibly absurd statements were made. Of course, well-informed persons know better. The keepers of reptiles at the New York Zoölogical Park, for example, find that snakes show no liking for milk. Captive specimens cannot be induced to drink it unless suffering from great thirst. It would be a feat beyond physical possibility for a serpent the size of the largest milk snake to consume enough milk from a cow—if the reptile should be so inclined—to produce an effect noticeable to the most minute degree.
We will mention only one other sort of our harmless colubrines—the "hognose," "puffing adder," "spreading adder," as it is variously known; but the name hognose is the best. Its genus is Heterodon. Two species are common all over the eastern half of the United States and Canada, one an ugly mottled gray, the other black. They are about two feet in length, thick-bodied, with roughly keeled scales, a flat head and a pointed, upturned snout—altogether very unhandsome and forbidding-looking reptiles; and they profit by this in an attempt to frighten away whatever alarms them, while in reality themselves almost (sometimes quite) paralyzed by fear.
CORAL SNAKES, COBRAS, AND SEA SNAKES
The flattening of the head and neck practiced by the hognose as a gesture of readiness to fight, whether true or false in its implication of ability, is found among several non-poisonous colubrids elsewhere and indicates their approach in kinship to the "hooded" cobras that are the foremost representatives of the venom-bearing members of the Colubridæ. It will be recalled that we have been sketching the "harmless" section (Aglypha), and have now to take up the two remaining "dangerous" sections of the Colubridæ, the Opisthoglypha and the Proteroglypha.
The principal tooth-bearing bone in a serpent's mouth is the forward half of the upper jaw, termed the maxillary. The maxillary of each side is connected with its fellow by a small, single bone in front (the premaxillary) and otherwise is connected with the loosely connected bones of the skull by those elastic cartilages that enable the mouth to expand and take in prey of a size more than equal to the snake's head when the mouth is shut. In the serpents that do not possess a poisoning apparatus the teeth on the maxillaries are alike in size, and solid; but in the venomous kinds some of the teeth are enlarged and grooved or channeled to conduct a flow of poison into the wound made by biting. This is the case with the poison-bearing sections of the Colubridæ mentioned above, and their difference is in the relative position of the poison-conducting teeth or "fangs" on the maxillaries.