Grass SnakeNatrix natrixWhere and when to see them

The Grass Snake links the Donau-Auen floodplain’s water and land habitats. The national park calls it Austria’s most common snake and describes an excellent swimmer and diver that takes much of its prey in or beside water. Commonness does not remove its conservation needs: the park also reports an Austrian vulnerable listing. Source: https://www.donauauen.at/en/facts/nature-science/fauna-engl/grass-snake

Size

Males normally 60–70 cm (23.6–27.6 in); females 80–100 cm (31.5–39.4 in) total length in the Donau-Auen species account.

Weight

Species-specific weight not verified.

Lifespan

Species-specific lifespan not verified.

Status

Donau-Auen describes the species as vulnerable in Austria. A current formal global assessment was not verified.

A disturbed snake may slip quietly into water or another hiding place. The park describes communal overwintering in deep embankment cracks and old logs. Its 2025 account also records foul-smelling defensive secretions and death-feigning. These are defensive responses, not performances to provoke for photographs. https://www.donauauen.at/aktuelles/news/die-schlangen-der-auen-sind-erwacht

• It is an excellent swimmer.
• It also hunts on land.
• Females are usually longer than males.
• Pale neck patches have a dark rear border.
• Almost black individuals occur.
• Frogs and tadpoles are among its prey.
• Disturbed snakes may feign death.

The park describes overwintering and spring emergence, while the registry recommends warm-month bank watching. Neither establishes a recurring numerical visitor-observation calendar. Hibernation dates and mating dates are not converted into location months. Ask the park about current activity and trail conditions, and leave the month array empty.

The relevant reach is the Austrian Donau-Auen floodplain east of Vienna towards Hainburg, not other Danube cruise ports. Waterside banks, floodplain woodland and sheltered terrestrial refuges all matter. An animal may be seen swimming across quiet water or resting beside cover, making a permitted backwater walk more useful than open-channel deck watching.

Donau-Auen lists frogs, toads, salamanders, fish and tadpoles as prey, captured around water and swallowed alive. This makes the snake a predator within the floodplain food web rather than a threat to visitors. Local prey proportions and differences between male, female and juvenile diets were not verified.

Common name

Grass Snake

Scientific name

Natrix natrix

Animal group

Reptiles

Size

Males normally 60–70 cm (23.6–27.6 in); females 80–100 cm (31.5–39.4 in) total length in the Donau-Auen species account.

Weight

Species-specific weight not verified.

Lifespan

Species-specific lifespan not verified.

Status

Donau-Auen describes the species as vulnerable in Austria. A current formal global assessment was not verified.

Identification

The park describes grey, brown or olive upperparts, dark spotting and strongly keeled scales. Pale neck patches may be white, yellow or orange-red and are bordered towards the tail by black. Very dark individuals occur. Young Aesculapian snakes can also have a collar, so a pale neck patch alone is not conclusive.