How to Identify the Iberian Grass Snake (Identification Guide)
The Iberian Grass Snake is a water-loving natricine of the Iberian Peninsula, identified by its pale neck collar, keeled scales, and grayish-olive, lightly patterned body.
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Key identifying features
The Iberian Grass Snake (Natrix astreptophora) shares the general grass snake body plan, with a pale collar marking behind the head, though in this species the collar can be less prominent or more diffuse compared to other grass snake species. It is a medium to large natricine with keeled scales and a fairly plain dorsal pattern.
Coloration & pattern
The dorsal coloration is typically olive-gray, grayish-brown, or greenish, often with faint dark spotting or flecking rather than the bold barring seen in some related species. The collar behind the head is present but can be subtler, sometimes broken or less contrasted. The belly usually shows a checkered pattern of black and cream or pale gray.
Head, eyes & scales
The head is distinct from the neck and moderately broad, with round pupils typical of active, diurnal water-associated snakes. Scales are keeled, producing a slightly textured rather than glossy body surface.
Size & body shape
Adults typically range from 70-150 cm, with females generally larger than males, and a moderately stout body suited to both terrestrial foraging and swimming.
Range & habitat where you'll see it
The Iberian Grass Snake is found throughout the Iberian Peninsula (Spain and Portugal), typically near water sources such as rivers, streams, ponds, and irrigation channels, though it also ranges into drier surrounding habitat when foraging.
How to tell it apart from look-alikes
Compared to the Barred Grass Snake, the Iberian Grass Snake generally shows a more subdued, less strongly barred pattern and a subtler neck collar. It can be distinguished from vipers and other unrelated species by its keeled scales combined with round pupils and the (even if faint) pale collar mark, features vipers lack. Careful attention to the collar and flank pattern, along with its consistent association with freshwater habitats, helps confirm identification.
Frequently asked questions
How is the Iberian Grass Snake different from other grass snakes?
It typically shows a subtler, sometimes broken neck collar and a more faintly spotted pattern rather than bold barring.
Where is the Iberian Grass Snake found?
It occurs throughout Spain and Portugal, usually near rivers, ponds, and other freshwater habitats.
What kind of scales does it have?
Keeled scales, giving the body a slightly rough texture rather than a smooth, glossy look.
How large can this species grow?
Adults typically range from 70-150 cm, with females usually larger than males.
Does the Iberian Grass Snake always have a visible neck collar?
A collar is usually present but can be faint or partially broken, unlike the bolder collar of some other grass snake species.