Dice snake (Natrix tessellata)

Scientific classification:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae

The dice snake (Natrix tessellata) is a European nonvenomous snake belonging to the family Colubridae, subfamily Natricinae.

Brief description
Females are bigger than males. Maximum size is between 1.0-1.3 m (39-51 inches) long. The 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.

Biology
It feeds mainly on fish, though lives mainly nearby river streams or lakes. Sometimes it feeds also on amphibians like frogs, toads and tadpoles.

This snake is not venomous. As a defense it spreads a very bad smelling secretion from its cloaca. Another defence mechanism is thanatosis, that meaning the snake is playing dead.

During the mating season (March-April-May) they congregate in large groups. Egg 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 Europe and Asia: Lebanon, Israel, Germany, Switzerland, Austria, France, Croatia, Slovenia, Bosnia and Herzegovina, Montenegro, Republic of Macedonia, Serbia, Italy, Czech Republic, Slovakia, Poland, Albania, Romania, Bulgaria, Hungary, Turkey, Greece, Cyprus, Afghanistan, Russia, Ukraine, Armenia, Georgia, Azerbaijan, Kazakhstan, Turkmenistan, Tajikistan, Uzbekistan, Kyrgyzstan, Iraq, Syria, Jordan, Yemen, Egypt, Pakistan, China.

Research projects
One of the most numerous population lives in the vicinity of the ruins of Histria, in Dobrogea region, Romania. This population has been recently discovered to be threatened by a parasitic nematode, namely Eustrongylides. Since 2005, the population from Histria has been in researchers' attention. The Tessellata project, a joint Romanian-Swedish-Czech research program, is focused on population biology studies and parasitic threats of this unique costal population.