VIPERS, a family (Viperidcne) of venomous snakes belonging to the suborder SolesioglyPha and closely related to the Crotalicke, or pit vipers and rattlesnakes. In the character of the poison apparatus the vipers closely resemble the rattlesnakes, under which heading a full description will be found, but they differ as a family from the Crotalide in lacking the pre orbital sensory pit and the excavation of the maxillary bone for its accommodation. None of them have the tail terminated by a ratde; but in form, scale characters and habits they ex hibit much the same range of variations as the various genera and species of the vit-vipers. Their distribution, however, is totally different, for while the Crotalidce are scarcely represented outside of America the ViPeridee are absolutely confined to the tropical and temperate regions of Europe, Asia and Africa, the latter having the .greatest number and most formidable species. The family embraces 40 or 50 species, many of which are variable. The typical vipers are the characteristic poisonous snakes of most of Europe and belong to the genus ViPera, which has two rows of scales or urosteges on the short tail, the head covered almost exclu sively with numerous srnall scales, with those at the end of the snout and above the eyes often turned upward, and the body-scales keeled.
The common viper or adder (Vipera berus) is found throughout most of temperate Europe, including England and Scotland, but is absent from large areas, while in others of different geological formation and even in well-cultivated districts it is common. It attains a length of from one and one-half to two feet, and is variously colored. Its most frequent and stable markings appear to be a brownish-yellow ground, with a series of continuous zigzag markings along the back, and a set of triangular black spots along each side. Specitnens are fre quently found with light tinti sbrnetimes nearly black. The viper is the only poisonous reptile of Britain. Its bite is seldom productive of fatal consequences, but may induce pain, sickness, fever and even delinum and as a sequence a protracted period of nervousness and a tendency for tke wound to supPurate. The effects have been known to persist for a fort night or more; and in children a fatal result has occasionally followed the adder's biteu The food consists of frogs, mice, birds, eggs, and they hunt chiefly at night, quartering the ground systematically and following the runways of meadow mice. The viper as viviparous— re taining its eggs within the body till the young are hatched, and the young are known to habitually retreat into the mouth and ce-sophagus of the mother when threatened by danger. Like the rattlesnalce vipers often collect in large numbers in caves and holes during the season of hibernation.
The common asp of southwestern Europe (V. aspis) has the snout plate turned up
ward, a character which is much exaggerated in the prominent nasal horn of V. ammodytes, of southeastern Europe. Supra-orbital horns, re calling those of the horned rattlesnake of the southwestern United States, are found in Cerastes and Clotho. The fortner inhabit the hot desert-region of northern Africa and south western Asia, one small and very venomous scies being the horned viper (C. cortsutus). The asp used for suicide by Cleopatra, and of Scripture is not a viper but one of the cobras (Naja bait). To Clotgo belong the large and dangerous rhinoceros-vipers of Africa. One of the most dreaded serpents of Africa is the puff adder (Bitis arietans) which, besides some dif ferences in arrangement of tht head-scales in cluding the absence of any horns, has the nos trils directed nearly upward, It reaches a length of five feet, and is of robust build, its apparent size being further enhanced by its habit of puffing up, the body when molested. The puff adder inhabits dry plains throughout the greater part of Africa and like the horned vipers con, ceals itself by partially covering its body with loose earth. In general habits it resembles the European vipet but is rnore sluggish, and owing to its large size and the virulence of its venom is exceedingly dangerous to man.and beast. Its bite is followed by the most severe constitutional and local symptoms, including a rapid aud pro gressive gangrene. In Africa are found also the tree-vipers (Allstria), small snakes with pre hensile tails and usually bright green colors. Several species of vipe'rs are among the most poiscmous snakes of India and contribute largely to the number of fatalities resulting from snake bites in that country. The most notable are Russell's viper or ticpolonga (Daboia reaching a length of five feet, and the little, bat for that reason even more dangerous, krait (Echis carinata). The name viper is also ap plied erroneously to several American snakes, especially to the copperhead and moccasin (qq.v.) and to the hog-nosed snake (q.v.), die last of which is quite harmless, notwithstand ing its unfortunately had reputation and threat erung appearance.
A number of mostly small, poisonous snalces of Africa and India have been separated from the Viperide under the names Consider and Atractaspide. They differ variously in having large head plates, grooved fangs, no postfrontal bone or in being oviparous. The vipers of Australia are related to the cobra de capello (q.v.) and belong to the family Najide.
Consult Boulenger, (Catalogne of Snakes of the British Museum) (London 1896); Gunther, (Reptiles of British India) (London 1864)1 Boulenger, (Reptiles of British India) (London 1890) ; Anderson, (Zoology of Egypt,) Vol. I (London 1898).