Dice snakes in the Troja Basin

PPhoto: Mikuláš Velenský, Prague zoo

We help dice snakes

Prague Zoo has been conducting research into the Troja population of dice snakes and incorporating the acquired knowledge in zoo development planning. In order to help dice snakes, we take care of the vast areas of their wintering grounds in the rocky massive along Zakázanka path and strive to reduce the dangers of their annual migration across the busy road along the river.

Important notice

Snakes moving freely in the zoo premises are not dangerous to people and have not escaped from exhibits.

If you find a dice snake, do not catch it, carry it, or stay near it unnecessarily. A disturbed dice snake frequently reacts by going stiff or ‘playing dead’. It will stay this way for as long as you watch it. As soon as you leave, the snake will rapidly continue its journey and find a hideaway.

More about snakes

Dice snake (Natrix tessellata) 
The dice snake is one of the rarest reptiles found in the territory of Czech Republic – in Bohemia, the non-venomous, non-aggressive snake is found only in several patches on the warm canyon slopes of the Vltava, Berounka and Sázava rivers and is protected by Czech laws as a critically endangered species. The Troja population is one of the largest.

Way of life

Dice snakes stay near water, where they catch fish and amphibians. They are excellent swimmers and swallow smaller prey directly in water. Sometimes they are mistaken for vipers. However, unlike vipers, the black spots on their back never merge to form a connected zigzag line; on the contrary, the spots are frequently arranged like a chessboard.

Dice snakes at the zoo

• The summer hunting grounds and places where dice snakes reproduce are situated near the dike slope along the southern fence of the zoo. The snakes spend most of their days sunbathing there; however, they are very inconspicuous.
• Before winter, the dice snakes move to the dry stony slopes along Zakázanka and Geostezka paths. For winter they select hideaways which do not freeze through and are outside the reach of possible spring floods.
• The dice snakes migrate through the zoo area twice a year.
  
  • The autumn migration from the river to the rocks takes two months. The first females leave for the winter grounds at the beginning of August. In September and October, you can even find freshly-hatched young ones measuring around twenty centimeters.
  • The spring migration, which starts in mid-April, is highly visible: a long stream of snakes sets off from the winter grounds in the rocks to the river.