582 



THE NATURE BOOK 



group, such as the Hamadryad (" King 

 of the Cobras"), the ordinary Cobra, and 

 the Black Snake of Australia, which have 

 teeth in the front part of the upper jaw- 

 grooved or perforated. The venom of the 

 Cobra is considered to be sixteen times as 

 powerful as that of the Adder, and it has 

 been estimated that -015 of a gramme of 

 its venom will kill a human being. 



EGGS OF THE GRASS SNAKE. 



More than a thousand species of Colu- 

 brine snakes have been distinguished. 



They have, as might be expected from 

 their multitude, a world-wide distribution 

 (the only impassable barrier to snakes on 

 a continent is the line of permanently 

 frozen ground), and they include aquatic, 

 semi-aquatic, arboreal and terrestrial 

 species. Our own Grass Snake may be 

 reckoned as semi-aquatic. He is, at the 

 same time, an excellent climber. His 

 slough is usually found a foot or so 

 above ground level, and he runs the 

 hedgerow in search of eggs and nestlings. 

 Where both he and the Adder are found in 

 the same county, it is the Grass Snake 

 who prefers the low-lying damp situa- 

 tions, while the Adder is more usually in 

 evidence on the dry heights. Wliere no 

 high ground exists — as in the Fens, or 

 the Essex marshes — the Adder frequents 

 the highest points available— the dyke- 

 banks, for example. 



In coloration the Grass Snake may 

 easily be distinguished even from a dingy 

 Adder. The yellow collar round his neck, 

 frorn which is derived his alternative 

 name of " Ringed " Snake, is a distinctive 

 character, and, so far as British Grass 



Snakes are concerned, practically in- 

 variable. It is thrown into strong relief 

 by the darkening of the scales behind it. 

 In the newly hatched young (I may 

 mention that Grass Snakes' eggs can 

 easily be hatched in a hothouse where the 

 temperature is maintained above 60° F.) 

 the collar is of a blue-grey colour, but 

 in a few days' time it acquires the yellow 

 tint, and is even more conspicuous in a 

 young, round-eyed, large-headed snakeling 

 than in a mature snake. On rare occasions 

 the blue-grey collar persists as a whitish 

 colour in the adult. 



The body-colour of the young may be 

 described as a dark green-olive. In the 

 mature specimen it varies with the age 

 of the skin, and, to some degree, I think, 

 with the locality " Olive " describes it 

 fairly enough, for the variations of tint 

 which it displays correspond pretty 

 closely with the variations in the dinner- 

 table olive. 



Along the Grass Snake's sides are 

 irregular black spots, and beneath these 

 are to be found vertical black hatchings. 



The scales, compared with those of the 

 Smooth Snake, are keeled, but their 

 " mid-rib " is not so evident as is the 

 case with the Adder. 



A Grass Snake's food normallv consists 

 of amphibians and fish. Several instances, 

 however, have been recorded of his 

 swallowing mice and small birds, and 

 there is one curious record {Field Natur- 

 alist's Quarterly, Nov., 1903) of his swallow- 

 ing a mole. 



In swimming the Grass Snake holds his 

 head six to eight inches above water, and 

 proceeds by an eel-like undulation of the 

 trunk and tail. To catch fish, he must, 

 of course, plunge his head below the 

 surface, but he follows the habit of most 

 semi-aquatic creatures in bringing his 

 prey ashore to eat it. This procedure 

 is forced on him. As we have noted in 

 the case of the Adder, a snake swallows 

 by working himself outside his victim 

 rather than by ingurgitation, and, to do 

 this, he must have something solid both 

 to push off from and to push against. 

 The Grass Snake has no teeth to corre- 

 spond with the poison fangs of the Adder, 

 but is well provided with small teeth, 

 having four rows in both the upper and 

 the under jaws. All these teeth are 



