Chapter XII: Distribution

Representatives of the order Ophidia are found over the whole world, with the exception of Iceland, Ireland, and New Zealand, between the Northern limit of 67° in Europe (_Vipera berus_), 60° in Asia (_Vipera berus_), and 52° in America (_Tropidonotus ordinatus_), and the Southern limit of 44° (_Philodryas schotti_). The highest altitudes reached by them are 14,000 feet in the Himalayas (_Tropidonotus baileyi_), 9,700 feet in the Alps (_Vipera aspis_), and 9,000 feet in the Andes (_Liophis albiventris_). They are most numerous between the tropics, and the number of species gradually diminishes to the North and South.

For the purpose of showing the distribution of the principal groups, we will follow the divisions into families and subfamilies enumerated above (p. 4).

_Typhlopidæ._--S.E. Europe, S. Asia, Africa, Australia (exclusive of Tasmania), C. and S. America, and W. Indies.

_Glauconiidæ._--S. Asia (as far E. as Sind), Africa (exclusive of Madagascar), C. America (extending into the S. parts of N. America), S. America.

_Pythoninæ._--S. Asia, Africa (exclusive of Madagascar), Australia (exclusive of Tasmania), C. America.

_Boinæ._--S.E. Europe, C. and S. Asia, N. Africa, Madagascar, Mauritius, W. Polynesia, S.W. of N. America, C. and S. America, and W. Indies.

_Ilysiidæ._--S.E. Asia, S. America.

_Uropeltidæ._--India and Ceylon.

_Xenopeltidæ._--S.E. Asia.

_Acrochordinæ._--S.E. Asia, C. America.

_Colubrinæ._--The whole range of Ophidia, except Tasmania.

_Dasypeltinæ._--Africa (exclusive of Madagascar).

_Homalopsinæ._--S.E. Asia, N. Australia.

_Dipsadomorphinæ._--S. Europe, C. and S. Asia, Africa, Australia (exclusive of Tasmania), C. America (extending into the S. parts of N. America), S. America.

_Elachistodontinæ._--India.

_Hydrophiinæ._--Indian and Pacific Oceans.

_Elapinæ._--S. Asia, Africa (exclusive of Madagascar), Australia and Tasmania, Fiji Islands, C. America (extending into the S. parts of N. America), S. America.

_Amblycephalidæ._--S.E. Asia, C. and S. America.

_Viperinæ._--Europe, Asia, Africa (exclusive of Madagascar).

_Crotalinæ._--S.E. Europe, Asia, America.

The Zoogeographical Regions into which the world is usually divided (Palæarctic or Europo-Asiatic, Oriental or Indian, Ethiopian or African, Australian, Nearctic or North American, Neotropical or South American) do not lend themselves any better than the ordinary divisions of physical geography to the study of the distribution of Snakes. Contrary to what we find in dealing with the Tortoises, Australia does not show any special affinity to South America, and, as in the case of the Lizards, it must be regarded as an impoverished extension of the Indo-Malay fauna; as with the Lizards, also, Europe and Africa hang together, whilst Madagascar stands apart, distinguished by many negative features and some points of agreement with South America (Boidæ). There is a greater difference between the Snakes of Europe and those of Eastern Asia than there is between the latter and those of North America, whilst in Lizards a primary distinction must be made between the Old World and the New. Southern Asia east of Persia (the Oriental Region) is the great Ophidian centre, all the groups mentioned above, with the exception of the Dasypeltinæ, having representatives within its limits, and a large and very distinct family, the Uropeltidæ, being confined to it. The Pythoninæ occur along with the Boinæ, the Viperinæ with the Crotalinæ, and the Elapinæ are represented by varied forms, as they are also in Africa and still more in Australia, where they form the overwhelming majority, and in some parts, as well as in Tasmania, the exclusive Ophidian population. The coasts of India and Malaya are also the home of the great majority of the Hydrophiinæ. Large genera like _Tropidonotus_, _Zamenis_, and _Coluber_, extend over the Europo-Asiatic and North American regions, but they are equally well represented in the Oriental. The great difference between Madagascar and Africa is, as we have said, very striking. Madagascar possesses Boidæ generically identical with those of South America, but otherwise only Typhlopidæ, Colubrinæ, and Dipsadomorphinæ; whilst in the greater part of Africa the Boinæ are replaced by the Pythoninæ, and the Glauconiidæ, Elapinæ, and Viperinæ are generally distributed. North America agrees with Asia and South America in its Crotalinæ, otherwise its Ophidian fauna is not very different from that of Europe, although much richer, and South America shares the Glauconiidæ with Africa and the Ilysiidæ with Southern Asia. South America is rich in Colubrinæ and Dipsadomorphinæ, nearly all generically different from those of other parts of the world, and the Elapinæ are represented by the single genus _Elaps_, with many species, two of which extend to the southern parts of North America.

This rapid sketch of the principal facts of Ophidian distribution suffices to show how difficult it would be to frame geographical regions that would give expression to these facts. Such regions would necessarily be very different from those adopted in dealing with the distribution of the other divisions of the class Reptilia. This is a task which need not be attempted on the present occasion.

A few words as to the salient characters of the European fauna, which is a poor one as compared with other parts of the world. The single species of the genera _Typhlops_ and _Eryx_ must be regarded as outposts from South-Western Asia; the single species of _Ancistrodon_, which extends from Central Asia into a very small territory to the south-east, is also an Asiatic type. The genera _Tropidonotus_, _Zamenis_, _Coluber_, _Coronella_, and _Contia_, are characteristic of the Northern Hemisphere, and the first three are, besides, equally well represented in the Oriental region; a few species of _Tropidonotus_ are also found in Africa and Madagascar. _Coelopeltis_, _Macroprotodon_, and _Tarbophis_ are the northern outposts of an Afro-Indian group, although, with the exception of the third, exclusively confined to the circum-Mediterranean district. The genus _Vipera_ is also represented in East Africa and in Southern Asia, but the species _V. berus_ is essentially a northern type, extending to the highest latitude reached by any snake, and ranging all over Northern Asia to the Amur and Sachalien. The same species reaches the greatest altitude at which any snake has been observed on the northern side of the Alps--viz., 9,000 feet.

Of the twenty-eight species inhabiting Europe, only two are generally distributed: _Tropidonotus natrix_ and _Coronella austriaca_. One is to be regarded as a northern form, although occurring locally in the south: _Vipera berus_. It is the reverse with _Coluber longissimus_. The others may be described as southern forms, two only as ranging from west to east: _Zamenis gemonensis_ and _Coelopeltis monspessulana_; one of more central habitat: _Vipera ursinii_. The remainder may be divided into two groups--those of more western, and those of more eastern distribution. To the first group belong _Tropidonotus viperinus_, _Zamenis hippocrepis_, _Coluber scalaris_, _Coronella girondica_, _Macroprotodon cucullatus_, _Vipera aspis_ and _Vipera latastii_; to the second, _Typhlops vermicularis_, _Eryx jaculus_, _Tropidonotus tessellatus_, _Zamenis dahlii_, _Coluber quatuorlineatus_, _dione_, _leopardinus_, _Contia modesta_, _Tarbophis fallax_ and _iberus_, _Vipera renardi_, _ammodytes_, _lebetina_, and _Ancistrodon halys_.

A remarkable fact in the distribution of European Snakes is the altitudinal range of _Vipera berus_, _V. aspis_, and _V. ursinii_. The first being the northernmost snake, generally distributed in Northern Europe and more locally in the south, should, one would expect, be a mountain form in the south. This is so in Switzerland, where it occurs chiefly between 2,500 and 9,000 feet, on the northern aspect of the Alps, whilst _V. aspis_ lives at altitudes below 5,000 feet; but on the southern aspect of the same chain things are reversed, and _V. berus_ is replaced by _V. aspis_, which reaches an altitude of 9,700 feet, whilst the former shows a tendency to abandon the mountains, and has established itself in a few localities in the plain of North Italy. Again, in France _V. berus_ is the northern and _V. aspis_ the southern species, yet the latter is the only one found on the French side of the Pyrenees (up to 7,250 feet), whilst the former reappears in North-Western Spain and Portugal at very low altitudes, even at sea-level. _V. ursinii_ is a mountain form in Italy (Abruzzi), in France (Basses-Alpes), and in the Balkan Peninsula (up to 6,800 feet); but it is restricted to the plain in Lower Austria and Hungary, where _V. berus_ occurs only in the mountains.

Only three species are entirely confined to Europe:

_Coluber scalaris_, _Vipera ursinii_, and _V. aspis_.

Of the species which range outside Europe, the following occur both in Western Asia and in North Africa:

_Eryx jaculus_, _Tropidonotus natrix_, _Coelopeltis monspessulana_, _Vipera lebetina_.

In Western Asia and the North-East of Egypt:

_Tropidonotus tessellatus_, _Zamenis dahlii_.

In Western Asia:

_Typhlops vermicularis_, _Zamenis gemonensis_, _Coluber quatuorlineatus_, _C. dione_, _C. longissimus_, _C. leopardinus_, _Coronella austriaca_, _Contia modesta_, _Tarbophis fallax_, _T. iberus_, _Vipera renardi_, _V. berus_, _V. ammodytes_, _Ancistrodon halys_.

In North Africa:

_Macroprotodon cucullatus._

In North-West Africa:

_Tropidonotus viperinus_, _Zamenis hippocrepis_, _Coronella girondica_, _Vipera latastii_.

The following lists will help to elucidate the distribution of the snakes in the different parts of Europe:

I. SCANDINAVIA

1. _Tropidonotus natrix_ (as far north as 65°).

2. _Coronella austriaca_ (as far north as 63°).

3. _Vipera berus_ (as far north as 67°).

II. GREAT BRITAIN

1. _Tropidonotus natrix_ (England and Wales, extreme south-east of Scotland).

2. _Coronella austriaca_ (Surrey, Berkshire, Hampshire, and Dorsetshire).

3. _Vipera berus._

III. BELGIUM AND HOLLAND

1. _Tropidonotus natrix._

2. _Coronella austriaca._

3. _Vipera berus._

IV. GERMANY AND DENMARK

1. _Tropidonotus natrix._

2. _Tropidonotus tessellatus_ (Middle Rhine and Moselle, Saxony).

3. _Coluber longissimus_ (Denmark, Schlangenbad, Treves).

4. _Coronella austriaca._

5. _Vipera berus._

6. _Vipera aspis_ (Black Forest, Lorraine).

V. FRANCE AND SWITZERLAND, EXCLUSIVE OF TICINO

1. _Tropidonotus natrix._

2. _Tropidonotus viperinus_ (as far north as South Brittany and Fontainebleau).

3. _Zamenis gemonensis_ (south, locally as far north as the Sarthe and Aube).

4. _Coluber longissimus_ (locally as far north as South Brittany, South Normandy, and Fontainebleau).

5. _Coluber scalaris_ (Mediterranean Littoral).

6. _Coronella austriaca._

7. _Coronella girondica_ (south and west as far north as the Charente-Inférieure).

8. _Coelopeltis monspessulana_ (Mediterranean Littoral).

9. _Vipera ursinii_ (Basses-Alpes).

10. _Vipera berus_ (as far south as the Loire basin, the Central Plateau, and the Alps).

11. _Vipera aspis_ (as far north as the Loire basin, Fontainebleau, and Lorraine).

VI. SPAIN AND PORTUGAL

1. _Tropidonotus natrix._

2. _Tropidonotus viperinus._

3. _Zamenis gemonensis_ (Catalonia).

4. _Zamenis hippocrepis_ (absent from the north).

5. _Coluber longissimus_ (Andalucia).

6. _Coluber scalaris._

7. _Coronella austriaca_ (north and north-west).

8. _Coronella girondica._

9. _Coelopeltis monspessulana._

10. _Macroprotodon cucullatus_ (centre and south, Baleares).

11. _Vipera berus_ (north-west).

12. _Vipera aspis_ (Pyrenees).

13. _Vipera latastii_ (absent from the north).

VII. ITALY, WITH TICINO AND CORSICA

1. _Tropidonotus natrix._

2. _Tropidonotus tessellatus_ (as far south as Naples; absent from the islands).

3. _Tropidonotus viperinus_ (Liguria, Piedmont, Ticino, Corsica, Sardinia, Sicily).

4. _Zamenis gemonensis._

5. _Zamenis hippocrepis_ (Sardinia).

6. _Coluber quatuorlineatus_ (south and Sicily).

7. _Coluber longissimus_ (absent from Corsica).

8. _Coluber leopardinus_ (south and Sicily).

9. _Coronella austriaca_ (absent from Corsica and Sardinia).

10. _Coronella girondica_ (absent from Corsica and Sardinia).

11. _Coelopeltis monspessulana_ (Western Liguria, Sicily).

12. _Vipera ursinii_ (Abruzzi).

13. _Vipera berus_ (the Continental part only).

14. _Vipera aspis_ (absent from Corsica and Sardinia).

15. _Vipera ammodytes_ (Northern Venetia).

VIII. AUSTRIA-HUNGARY, WITHOUT BALKAN STATES

1. _Tropidonotus natrix._

2. _Tropidonotus tessellatus._

3. _Zamenis gemonensis_ (South Tyrol, Littoral, South Hungary).

4. _Coluber quatuorlineatus_ (Istria).

5. _Coluber longissimus._

6. _Coluber leopardinus_ (Istria).

7. _Coronella austriaca._

8. _Coronella girondica_ (South Tyrol).

9. _Coelopeltis monspessulana_ (Istria).

10. _Tarbophis fallax_ (Istria).

11. _Vipera ursinii_ (Lower Austria, Littoral, Hungary).

12. _Vipera berus._

13. _Vipera aspis_ (South Tyrol, Littoral).

14. _Vipera ammodytes_ (South Tyrol, Styria, Carinthia, Carniola, Littoral, South Hungary).

IX. BALKAN PENINSULA AND ARCHIPELAGO

1. _Typhlops vermicularis_ (Greece, Turkey, Bulgaria).

2. _Eryx jaculus_ (Greece, Turkey, Roumania).

3. _Tropidonotus natrix._

4. _Tropidonotus tessellatus._

5. _Zamenis gemonensis._

6. _Zamenis dahlii_ (coast of the Adriatic, Greece).

7. _Coluber quatuorlineatus._

8. _Coluber longissimus._

9. _Coluber leopardinus._

10. _Coronella austriaca._

11. _Coelopeltis monspessulana_ (West Coast, Greece, and islands).

12. _Tarbophis fallax_ (West Coast, Greece and islands, Constantinople).

13. _Vipera ursinii_ (Bulgaria, Bosnia, Herzegovina, Montenegro).

14. _Vipera berus_ (Bosnia, Herzegovina, Roumania).

15. _Vipera aspis_ (Bosnia).

16. _Vipera ammodytes._

17. _Vipera lebetina_ (Cyclades).

X. RUSSIA

1. _Tropidonotus natrix_ (as far north as 60°).

2. _Tropidonotus tessellatus_ (south).

3. _Zamenis gemonensis_ (south).

4. _Zamenis dahlii_ (Caucasus).

5. _Coluber quatuorlineatus_ (south).

6. _Coluber dione_ (south, between Volga and Ural).

7. _Coluber longissimus_ (south, Poland).

8. _Coluber leopardinus_ (Crimea).

9. _Coronella austriaca_ (as far north as 57°).

10. _Contia modesta_ (Caucasus).

11. _Tarbophis iberus_ (Caucasus).

12. _Vipera renardi_ (south).

13. _Vipera berus_ (as far north as 64°).

14. _Ancistrodon halys_ (south, between Volga and Ural).

Without attempting anything like a complete bibliography, we have compiled a list of faunistic works and papers dealing with the snakes of Europe:

EUROPE IN GENERAL

SCHREIBER, E.: Herpetologia Europæa. Zweite Auflage, Jena, 1912, 8vo.

STEINHEIL, F.: Die Europaeischen Schlangen. Kupferdrucktafeln nach Photographien der lebenden Tiere. Jena, 1913, 4to. (in progress).

GREAT BRITAIN

BELL, T.: A History of British Reptiles. 2nd edit., London, 1849, 8vo.

COOK, M. C.: Our Reptiles. London, 1865, 8vo.

LEIGHTON, G.: The Life-History of British Serpents. Edinburgh and London, 1901, 8vo.

FRANCE

GADEAU DE KERVILLE, H.: Faune de la Normandie. IV. Reptiles. Paris, 1897, 8vo.

LATASTE, F.: Essai d'une Faune Herpétologique de la Gironde. Bordeaux, 1876, 8vo.

MARTIN, R., ET ROLLINAT, R.: Vertébrés sauvages du Département de l'Indre. Paris, 1894, 8vo.

SWITZERLAND

FATIO, V.: Faune des Vertébrés de la Suisse. III. Reptiles et Batraciens. Geneva and Basle, 1872, 8vo.

SPANISH PENINSULA

BOSCÁ, E.: Catalogue des Reptiles et Amphibies de la Péninsule Ibérique et des Îles Baléares (Bull. Soc. Zool. France, 1880).

ITALY

BONAPARTE, C. L.: Iconografia della Fauna Italica. II. Anfibi. Rome, 1832-1841, fol.

CAMERANO, L.: Monografia degli Ofidi Italiani (Mem. Acc. Torin., [2] xxxix., 1888, and xli., 1891).

GERMANY

DÜRIGEN, B.: Deutschlands Amphibien und Reptilien. Magdeburg, 1890-1897, 8vo.

LEYDIG, F.: Ueber die Einheimischen Schlangen (Abh. Senck. Ges., xiii., 1883).

AUSTRIAN EMPIRE

WERNER, F.: Die Reptilien und Amphibien Oesterreich-Ungarns und der Occupationsländer. Vienna, 1897, 8vo.

GREECE

BEDRIAGA, J. DE: Die Amphibien und Reptilien Griechenlands (Bull. Soc. Nat. Mosc., 1881).

BORY DE ST. VINCENT, J. B.: Expédition Scientifique de Morée. Reptiles. Paris, 1832-1835, 4to., fol. atlas.

BULGARIA

KOWATCHEFF, W. T.: Herpetological Fauna of Bulgaria. Philippopolis, 1912, 8vo. [Bulgarian text.]

ROUMANIA

KIRITZESCU, C.: Contribution à la Faune Herpétologique de Roumanie. Sauriens et Ophidiens (Bull. Soc. Rom. Bucarest, x., 1901).

RUSSIA

NIKOLSKY, A.: Herpetologia Rossica. St. Petersburg, 1905, 4to. [Russian text.]

STRAUCH, A.: Die Schlangen des Russischen Reichs. St. Petersburg, 1873, 4to.

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