Grass snake
Natrix natrix
The grass snake is a medium-sized, non-venomous snake widely distributed across Europe and Asia. It is characterized by distinctive yellow or whitish collar markings behind the head. As a semi-aquatic species, it prefers habitats near still or slow-moving bodies of water. Its diet primarily consists of amphibians such as frogs and toads.
Details
Identification
Yellow to white collar marks, round pupils, keeled scales, usually grey to olive-green base color with black spots.
Social behavior
Generally solitary, but forms aggregations during mating ('mating balls') and in hibernation sites.
Diet
Feeds almost exclusively on amphibians (frogs, toads, newts), occasionally also fish or small mammals.
Hunting strategy
Active searching both on land and in water; prey is located visually and by scent, then swallowed alive.
Spawning substrate
Warm, decomposing organic material such as compost, manure heaps, or rotting wood.
Overwintering
Hibernation in frost-free underground burrows, compost heaps, or tree stumps from October to April.
Ecology
Ecological role
Important predator in aquatic and terrestrial ecosystems; serves as prey for birds of prey and predatory mammals.
Natural predators
Grey heron, common buzzard, white stork, hedgehog, fox, marten.
Competitor species
Other amphibian eaters like the grey heron or the dice snake (in overlapping habitats).
Ecosystem service
Regulation of amphibian populations.
Threats
Loss of wetlands, destruction of egg-laying sites, road traffic, and decline of amphibian populations.
Scientific profile
Profile
Distinguishing features
Light collar patches, round pupils, keeled scales. When threatened, it often exhibits thanatosis (death-feigning) or discharges a foul-smelling secretion from the post-anal glands.
Habitat
Highly water-dependent: riparian zones of lakes, ponds, flowing waters, bogs, wet meadows. Also found in structurally rich gardens, quarries, and forest edges near water bodies.
Diet
Primarily amphibians (frogs, toads, newts, and their larvae). Occasionally fish, more rarely small mammals or lizards.
Role in food web
Important predator of amphibian populations. Itself prey for birds of prey (e.g., Short-toed Eagle), herons, storks, hedgehogs, martens, and domestic cats.
Protection & threats
Main threats
Loss and fragmentation of wetlands, drainage of breeding ponds, loss of egg-laying sites (removal of compost/manure), road mortality during migrations.
Population trend
On the early warning list (V) in Germany; populations in intensively used agricultural landscapes are declining sharply.
Conservation measures
Protection and networking of wetland habitats, creation of artificial egg-laying sites (snake mounds), maintenance of buffer zones near water bodies.