Some snakes are adapted to arboreal life, some to the sand dunes of deserts and others to the freshwater, like many Natricidae species. In this family, various genus are spread all over the world, like the genus Natrix (water snakes) in Europe and North Africa, Thamnophis (garter snakes) in North America, Amphiesma (Keelbacks) in Asia and many others.
Four species belong to the water snakes genus: N. maura, N. megalocephala, N. natrix and N. tessellata. The lastone, also called dice snake, is the most apt to freshwater life, its eyes and nostrils are oriented slightly upwards, in order to see and breathe easily with most of their bodies underwater. The dice snake is thus an excellent swimmer, being however slower on the ground.
Many studies on the diet of this species show that it mainly eats small-medium size fish and a small percentage of amphibians.
Dice snakes usually live in wetlands (swamps and lakes), streams and slow-flowing rivers.
Sometimes, the dice snake can be confused with the viperine snakes (N. maura), that similarly live in aquatic environments, although being less adapted to live there. Consequently, they also eat fish, but considerably less than N. tessellata; conversely they eat more amphibians, like frogs and newts, and lots of invertebrates.
In order to distinguish dice and viperine snakes, we must observe their skin pattern and coloration, that in viperine snake is crisper than in the other. Furthermore, upon a closer inspection of the animal, many dissimilarity in the number of scales can help distinguish the two species.
"Grass snake" (N. natrix) and “Large headed water snake” (N. megalocephala) are less dependent on wetlands. In order to distinguish them from the other two species a useful characteristic is the white/yellow collar around the neck.
These snakes are totally harmless: if they are stressed or attacked by a predator, they don’t start to bite. Instead, they defecate and release a revolting smell from a gland inside the cloaca. This particular behaviour is called "thanatosis", that is the ability to fake death, with the head turned upside-down, the mouth open and the toungue out.