The Dryadinæ are chiefly American, and do not call for particular further remark; but the Natricinæ are very numerous, and there are three species in Europe of its most prominent genus, Tropidonotus—viz. T. natrix, T. hydrus, and T. viperinus. [Dr. Günther gives as many as twenty-one species of this genus as inhabitants of the Indian region alone, and there is reason to believe that that number is far from being complete. Others inhabit North America and North-western Australia, and some generic groups have been detached that are not very conspicuously separable.]
Fig. 11.—Ringed Snake (Tropidonotus natrix).
The Ringed Snake, Tropidonotus natrix, is often found in fine seasons near human habitations. It deposits its eggs, which are fifteen to twenty in number, commonly in dunghills, in one agglutinated mass. Exposed to the air, these eggs soon shrivel and dry, and the embryos within them perish. The Ringed Snakes are also found near rivers and meadows, by the side of water-courses, into which they love to plunge; hence they are sometimes called Water Serpents, Swimming Serpents, Hedge Eels, and other provincial synonyms. They sometimes attain to as much as and more than a yard in length. The summit of their head is covered with nine large scales, disposed in four rings. The upper part of the body is of a more or less darkish grey colour, marked on each side with irregular black spots. Between the two rows of spots are two other longitudinal rows, which extend from the head to the tail. The belly varies from black to a bluish white. Upon the neck are two whitish or pale yellowish spots, which form a kind of half collar or ring, from which its name is derived; these two spots become much more apparent from being contrasted with two other very dark triangular spots placed near them. They prey upon lizards, frogs, and mice, and they even surprise young birds, and devour the eggs in their nests, for they climb trees with facility. Towards the end of the autumn they seek the warmest places, approaching near to houses; or they retire into subterranean holes, often at the bottom of some hedge, which is almost always in an elevated place, secure from inundations. The Ringed Snake is found in nearly all European countries, and can be handled without danger. Lacépède gives some interesting details, showing the gentleness of its habits. They are easily tamed, and can be kept in houses, where they soon accustom themselves to those who have the care of them. At a sign from their keeper, they will twist themselves round his fingers, arms, and neck, insinuate their heads between his lips to drink his saliva, and to hide and warm themselves they creep under his clothes. In their wild state, the adult Ringed Snake lives in the fields; and, when full-grown, shows great irritation when attacked. When exasperated, they move their tongues, erect themselves with great vivacity, and even bite the hand which tries to seize them; but their bite is quite harmless.
[This Ringed Snake is the Natrix torquatus of Ray, well known to naturalists. The female is larger than the male. Its food consists a good deal of frogs, which are generally caught by the leg, and swallowed alive, in spite of resistance and very distressing cries.
When the skin has just been cast, the Ringed Snake presents beautiful markings, especially when seen swimming across some clear running stream, its head and neck raised above the limpid water, and the sun shining on its bright enamelled skin. It has been supposed, not unnaturally, that the Snake casts its skin at fixed intervals; this, Mr. Bell considers to be a mistake. He has always found that it depended on the temperature of the atmosphere and on their state of health and feeding. "I have known the skin thrown off" he adds, "four or five times during the year. It is always thrown off by reversing it, so that the transparent covering of the eyes and that of the scales are always found in the exuviæ. Previous to this curious phenomenon, the whole cuticle becomes somewhat opaque, the eyes dim, and the animal is evidently blind. It also becomes more or less inactive, until at length, when the skin is ready for removal and the new skin perfectly hard underneath, the animal bursts it at the neck, and creeping through some dense herbage or low brushwood, leaves it detached, and comes forth in brighter and clearer colours than before."
The Ringed Snake begins to hybernate, in some warm hedge or under the root of some tree, or other sheltered situation, about the end of autumn; and there they coil themselves up, sometimes in numbers, till the spring again calls them forth. Many instances are told of this Snake being tamed. Mr. Bell had one which knew him from all other persons; it would come to him when let out of its box, and crawl under the sleeve of his coat, and every morning come to him for its draught of milk.]
The Green and Yellow Snake is also about a yard in length, and is common in the south and west of France; they have been taken in the forest of Fontainebleau. The beautiful colours in which they are clothed causes them to be easily distinguished from the Viper. The eyes are edged with golden-coloured scales; the upper part of the body is of a very dark greenish colour, upon which is extended a large number of radiating lines, composed of small yellowish spots of different shapes, some long, others lozenge shape, giving it a chequered appearance. These chequers extend from the head to the tail. The belly is yellowish; the large plates which cover it have a black spot at each end, and are bordered with a very thin black line. This inoffensive reptile is extremely timid, and generally hides itself from observation, taking to flight at the least alarm. They are said to be easily tamed.
Fig. 12.—Tropidonotus viperinus.