T. natrix, the common Grass-Snake, has a divided, or double, anal shield. The strongly keeled scales of the body form nineteen rows. There are normally seven upper labials, the third and fourth of which border the eye. The usual colour of the Grass-Snake is olive-grey or brown above, with black spots and narrow cross-bands. The labials are white or yellowish, with black sutures. The belly is checkered black and white, more or less suffused with grey. There are several colour-varieties. The typical or northern form has a white, yellow, or orange collar, bordered behind by a black collar; the pale collar is sometimes faint or absent. The second variety, rather common in Spain and Portugal, although not the only form in the Peninsula, has no collar whatever, and these specimens are sometimes almost uniformly grey-green above. The third variety, common in South-Eastern Europe and in Asia Minor, has a well-marked collar and a yellowish streak along each side of the back. But there are also almost black specimens.
The usual length of an adult female Grass-Snake is about 3 feet, but very exceptional cases of more than 6 feet are on record; the males are smaller and more slenderly built. The range extends over the whole of Middle Europe, Algeria, West and Central Asia. It does not, however, occur in Ireland or Scotland. Its northern limit is the southern part of Sweden.
The Grass-Snake prefers moist, grassy localities, with the neighbourhood of water, chiefly on account of the food, which consists entirely of fishes and Amphibia, notably of frogs; tree-frogs are preferred to anything else; toads are occasionally eaten, but mice are never taken.
The Grass-Snake can climb trees or rather shrubs and is an accomplished swimmer, often spending much of its time in water for fishing purposes. The fish is caught by the belly and then generally swallowed on land. The Grass-Snakes appear in the spring and disappear in the autumn to hibernate in the ground. They pair, in England, in the month of May or June, usually on warm and sunny mornings. The eggs are laid from July to the end of August, mostly in rich vegetable soil, in heaps of weeds or in manure-heaps. Young snakes lay fewer eggs than old specimens, which sometimes produce more than three dozen at a time. The eggs are soft, whitish yellow, about one inch long, and soon stick together, so that the whole clump can be taken up at once. As a rule the new-laid eggs do not contain any visible sign of the embryo, but it often happens that the snake has to delay oviposition, and then the embryos are more or less advanced. This is especially the case with recently caught specimens. The young are hatched in the late summer or in the autumn, and seem to live at first upon soft insects and worms. Curiously enough they are easily drowned when they fall into the water, even in a shallow tank. My tame snakes have often laid eggs between the stones in the greenhouse; the young throve well upon unknown food, but most of them met their fate in the water. When they are a few weeks old they are strong enough to take baby-frogs.
The Grass-Snake becomes very tame, learns to distinguish between different people, allows itself to be handled without hissing or without voiding the obnoxiously smelling contents of its cloaca and anal glands, will in time take the offered food from the hand, and will even crawl up the arm or sleeve and coil itself up contentedly. One of the finest specimens, quite green, without a trace of a collar, and with brownish-red eyes, I caught in the Guadiana, where it had been fishing in midstream. It swam towards the bank, dived, and hid itself at the bottom between rocks. This snake, a female, became very tame. It never hibernated, shed its skin regularly every few months, and grew within nine years from 35 inches to 42 inches in length.
The Grass-Snake is perfectly harmless: although hissing, and striking out furiously with its head, it never bites, not even when it is severely handled. Its only defence consists of the awful contents of the cloaca and the anal glands, the secretion of which smells of concentrated essence of garlic mixed with other indescribable odours. The wildest specimens I have ever met with inhabited a swamp with a little stream to the north of Oporto close to the coast. To my utter surprise some of them actually made for me, swimming along rapidly with the head erect, about 6 inches above the water, and darting forwards with widely opened jaws, but they did not bite. These and other kinds of allied snakes require to drink much and often. Occasionally they drink milk when this is offered them, but that they suck the udders of cows or the breasts of women is an idle fable.
T. viperinus.–The scales are strongly keeled and form twenty-one to twenty-three longitudinal rows. The third and fourth labials border the eye. The anal shield is divided. The eyes and nostrils are directed upwards instead of sidewards, in adaptation to the essentially aquatic habits of this species, which lives upon fishes and Amphibia. The general colour is grey to reddish brown, with a black zigzag band along the back and a lateral series of black, yellow-eyed spots. The belly is yellow or red, checkered with black.
Fig. 160.–Tropidonotus sirtalis. × ½.
The Viperine Snake bears a general resemblance to the common viper. It inhabits France, Italy, Spain and Portugal, and Morocco. Very large specimens attain a length of nearly 3 feet, but the ordinary size of adults is 2 feet. This snake spends most of its time in the water, but it is often found on land, basking on the top of a low wall or on a low shrub. It is exceedingly common in Spain and Portugal, where it inhabits almost every ditch, any standing water or slow river. In the Alemtejo, when during the rainless and hot summer the small rivers have nearly dried up, these snakes collect in great quantities in the remaining stagnant and muddy pools, and as the stock of suitable fish gets exhausted, are often reduced to a deplorably emaciated condition. By the month of August they have become so thoroughly aquatic that they cannot be kept alive in dry surroundings for twenty-four hours. Those which I collected generally died, apparently from some kind of cutaneous suffocation, during the night following their capture. Taken under other conditions they are very easily kept and tamed.