Dice snake

Brief description

Females are bigger than males. Maximum size is 1.0–1.3 metres (39–51 in) 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

Living mainly near river streams or lakes, it frequently feeds on fish. Sometimes it feeds also on amphibians like frogs, toads and tadpoles.

Classified as non-venomous, Natrix tessellata produces a potent antihemorrhagin in its serum and has been said to produce a neurotoxin through a gland in its mouth. As a defense it spreads a very bad smelling secretion from its cloaca. Another defence mechanism is thanatosis, playing dead.

During the mating season (March–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, North 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, Iran, Iraq, Lebanon, Syria, Jordan, Yemen, Egypt, Pakistan, China, India.

Research projects

One of the most numerous populations lives in the vicinity of the ruins of Histria, in the Dobruja region, Romania. This population has been recently discovered to be threatened by a parasitic nematode of the genus Eustrongylides. Since 2005, the population from Histria has been receiving researchers' attention. For example, a joint Romanian–Swedish–Czech research program is focused on population biology studies and parasitic threats of this unique coastal population. An overview on Biology, Distribution and Conservation is given by Mebert (2011).