The dice snake (''Natrix tessellata'') or water snake is a Eurasian nonvenomous snake in the family

Colubridae Colubridae (, commonly known as colubrids , from , 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest fossil species of the family date back to the Late Eocene epoch, with earlier origins suspected. C ...

, subfamily

Natricinae The Natricinae are a subfamily of colubroid snakes, sometimes referred to as a family (Natricidae). The subfamily comprises 36 genera. Members include many very common snake species, such as the European grass snakes, and the North American wa ...

. Its average length is . Body color may vary from greyish green to brownish or almost black, with dark spots on the back. The belly is sometimes vividly coloured in yellow or orange, with black spots, very similar to dice, hence the name.

Ecology

Living mainly near rivers, streams and lakes, it frequently feeds on fish. Sometimes, it feeds also on

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

such as

frogs A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough skin texture due to ...

, toads, and tadpoles. In one instance, a dice snake was even observed trying to feed on an

olm The olm () or proteus (''Proteus anguinus'') is an aquatic salamander which is the only species in the genus ''Proteus'' of the family Proteidae and the only exclusively cave-dwelling chordate species found in Europe; the family's other extant g ...

(''Proteus anguinus'') that had been flushed from a cave in

Bosnia and Herzegovina Bosnia and Herzegovina, sometimes known as Bosnia-Herzegovina and informally as Bosnia, is a country in Southeast Europe. Situated on the Balkans, Balkan Peninsula, it borders Serbia to the east, Montenegro to the southeast, and Croatia to th ...

following heavy rains. However, the snake was far too small to be able to consume the olm. While considered nonvenomous, ''N. tessellata'' produces a potent antihemorrhagin in its serum. As a defence, it spreads a very bad-smelling secretion from its cloaca. Another defence mechanism is thanatosis, playing dead. During the

mating In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. '' Copulation'' is the union of the sex organs of two sexually repr ...

season (March–May), they congregate in large groups.

Egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the ...

-laying is usually in July, and one clutch consists of 10–30 eggs. The young snakes hatch in early September. Dice snakes hibernate from October to April in dry holes near the water.

Distribution

The dice snake is found throughout much of central and eastern Eurasia, from Italy and Czechia in the west to Kyrgyzstan in the east, and from Ukraine in the north to Iran in the south.

Conservation

The species is considered to be of

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

in its overall range, although local populations may be more sensitive. For example, it is considered

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

in the Czech Republic, mostly due to destruction of habitats and the introduction of invasive

American mink The American mink (''Neogale vison'') is a semiaquatic species of Mustelidae, mustelid native to North America, though human introduction has expanded its range to many parts of Europe, Asia, and South America. Because of range expansion, the Am ...

Gallery

File:Dürigen, 1897, T07.JPG, Illustration of dice snake (top) and grass snake ('' Natrix natrix'') including underside File:Dicesnake umbriaitaly.jpg, In

Umbria Umbria ( ; ) is a Regions of Italy, region of central Italy. It includes Lake Trasimeno and Cascata delle Marmore, Marmore Falls, and is crossed by the Tiber. It is the only landlocked region on the Italian Peninsula, Apennine Peninsula. The re ...

, Italy

References

External links

List of reptiles of Italy The Italy, Italian reptile fauna totals 58 species (including introduced and naturalised species). They are listed here in three systematic groups (Sauria, Serpentes, and Testudines) in alphabetical order by scientific name. Sauria (lizards) ...

{{Authority control Natrix Reptiles of Europe Reptiles of Azerbaijan Reptiles of China Reptiles of Pakistan Reptiles described in 1768 Snakes of Jordan Reptiles of Russia