Reptiles & Amphibians of France - Viperine snake, Natrix maura

Viperine snake, Natrix maura
(Linnaeus, 1758)

History and origin
The Viperine snake was first described by Linnaeus in 1758. This species scientific name is Natrix maura. Natrix meaning water loving, aquatic. Maura is latin for Mauritania, the Mauritanian water snake.

Characteristics
They have a viper-like resemblance.

Description
=Size=
They hatch at around 15 cm, averaging around 40 cm but growing up to 76 cm.
=Morphology=
They are fragile as juveniles and young adults. When they reach a length of around 50 cm long, their body becomes more robust, but they are still slim and elegant. Their head is slim and rectangular. They have small eyes.
=Patterns & colours=
Highly variable; usually either gray with darker zig-zag markings and sometimes spots on the flanks. Other common colours are brownish-green with dark markings. Orange specimens are not rare. Also bilineata form (lined form): usual patterns plus two thin and usually yellow or creamy lines running down the back. Belly is checkered black and white.

Geographical range
Western Europe, the Iberian peninsula, France (except the north, limit at around Orléans), west of Switzerland, northwestern Italy, Sardinia, Mallorca and Menorca.

Subspecies
None described although there are many variations in pattern that might have been accepted subspecies before the age of molecular research came.

Sexual differences
Females are larger then the males, especially in late spring when they carry their eggs.

Seasonal variations
None.

Diet
Their main food source are amphibians of all genres, they eat mainly young water frogs (Pelophylax sp.) and tree frogs (Hyla ssp.) and tadpoles. Fish are also taken. Young snakes will feed on large water insects and more commonly tadpoles, small fish and earthworms.

Defensive habits
They may hiss loudly and/or emit a foul smelling liquid from the anal region when handled. Sometimes, a specimen may want to pass its self off for a viper and try more aggressive looking techniques to get its self out of trouble, this includes flattening their neck and head, hissing loudly and swinging out towards the predator as if they want to bite, usually keeping their mouth closed.

Reproduction
Breeding occurs in spring, a week after hibernation. After only a few weeks, about 10 (3 to 26) eggs are laid in a moist, warm spot, usually under hey piles, in rotting wood piles and similar places. Sometimes they lay their eggs communally with other Viperine snakes and sometimes also with Grass snakes. The eggs incubate for around 11 weeks before hatching.

Sexual maturity, life span
The adult life span for Natrix maura is about 20 years. Males reach their sexual maturity in their third year, whereas females mature in their fourth year at the earliest. The animals are about 30 to 60 cm when they reach sexual maturity.

Habits
A highly aquatic snake species; nearly always found close to water. They are diurnal. When they are disturbed, they usually swim away at high speed, almost always diving and hiding underwater among plants and stones.

Venom
This is a non-venomous snake.

Habitat
They live in moist areas, usually very close to streams, rivers, ponds... They are highly aquatic.

Predators
Their natural predators are various mammals such as foxes and cats; also birds of prey and carnivorous water insects.