The largest snakes of the natracinae taxon of water snakes are the natrix genera. Sea snakes are a completely different group of snakes. As a general rule, water snakes are freshwater snakes though some sea snakes inhabit large lakes. The grass snakes' nostrils point sideways, unlike the upturned nostrils of the more aquatic natrix maura and natrix tessellata species.
Natrix natrix subspecies classification is far from definite, with between eight to a dozen subspecies differentiated dependent on the source used. Hybrid grass snakes also serve to add to any confusion. Grass snakes are found throughout mainland Europe except northern Scandinavia, plus predominantly southern parts of the UK and many European islands, plus western Asia and north-west Africa.
Grass Snake Habitat
The grass snake's preferred habitat consists of wetlands with nearby open, drier areas. They are often found in or near water but are also found on moorland and in open woodland, disused quarries and gardens. Areas near ponds and lakes that are well-stocked with fish and the other aquatic prey will be inhabited by grass snakes.
Though a good swimmer, the grass snake can be found basking on grassy banks or soil. Grass snakes will roam large areas, though these are usually gravid females seeking sites to lay their eggs. In a similar fashion to slow worms, grass snakes will hide under suitable coverings whether they be natural, such as undergrowth or large stones, or discarded materials such as corrugated sheeting.
Grass snakes will share their habitat and occasionally dens with the common adder, as they are not usually in competition for prey, the adder tending towards rodents while the grass snake seeks its largely aquatic-related diet. Grass snakes will often group in numbers for hibernation, mating rituals and egg-laying. Declining amphibian populations are affecting the grass snake's range and numbers in some areas, so that conservation efforts are encouraging volunteers to provide suitable wild gardens with ponds to support the species.
Grass Snake Characteristics, Behavior and "Playing Possum"
Larger than adders and slow worms, the largest grass snakes are females that can reach five or occasionally even six feet in length. Males grow to around three feet long. Grass snakes have strong bodies, large mature adults being up to around two inches wide. Shed skins of grass snakes can often be found in one piece if they have not been snagged as the snake edged slowly forward out of the skin during the sloughing process.
Grass snakes can be olive, green, grey or brown in color, with darker spots, blotches and commonly, darker scales that form rings around the snake's body. The underside of a grass snake is usually black and white in a roughly chequered arrangement. There are variations in some sub-species, including the Balkan grass snake, natrix natrix persa, which has two longitudinal stripes. It is very unusual but still possible to find melanistic, single color, usually black, grass snakes occasionally.
A distinguishing feature of the grass snake is usually a pattern of the black and yellow markings behind its head, occasionally with flecks of white or orange in some subspecies. These are less pronounced and sometimes absent altogether in females. The "collar" effect of the neck markings is the clearest visible difference between grass snakes and smooth snakes, though smooth snakes are generally smaller and more slender than adult grass snakes.
Grass snakes have large eyes with round pupils, thus providing better vision for these diurnal hunters than the elliptical eyes needed by many, but not all, vipers. Grass snakes are not poisonous. They usually live on a diet of frogs, small fish, newts, lizards and occasionally small mammals and birds if opportunities arise.
Unlike ambush predators like rattlesnakes, grass snakes tend to hunt either by swimming or by poking their head around in vegetation intending to flush out prey which they catch very quickly, often before the prey has been able to move more than a few inches. Sharp teeth point backwards into the grass snake's mouth enabling it to grip slippery prey which is often swallowed whole. The snake recognises the prey is harmless and will often swallow live prey and crush it as it is digested.
The grass snake's normal behavior is to try and escape from humans and other potential predators, such as large birds and some larger fish. If confronted by humans, grass snakes can hiss but will rarely bite. It sometimes feigns death by lying on its back, with its mouth open and tongue out, sometimes even emitting blood in the process. It also often releases a disgustingly smelly liquid from its cloacal (anal) gland.
This behavior of "playing possum" or playing dead is known as thanatosis and the snake will quickly flee if and when the potential threat has gone. It is worth noting that while the grass snake has a reputation for being a major exponent of this practice, not all individual grass snakes do it.
The grass snake is oviparous, laying between ten and fifty eggs. The eggs are laid in decaying and rotting vegetation, including compost heaps. These are all locations in which the decomposing process is lending heat to the eggs. The female grass snakes will often return to the same site each year.
Grass snake eggs are left to incubate for two to three months. Dark-colored young hatch following incubation. They are about six inches long and are independent immediately. As the egg-laying period is often around the same time for groups of female grass snakes and suitable sites might be in short supply, large groups of eggs have been found at some sites. As these have been found to sometimes contain more than 1,000 eggs from different females, some areas can see something of a population explosion during these periods.
Ian Dutton - My writing is part of my lifelong fascination with all spects of plants and animals. My homepage at Naturepieces explains more. My ...
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