Grass Snake Part 1

Folded into the high moor between dark mats of heather, a shock of bright green moss skirts a ring of boggy pools. In one the water heaves and starts to boil as the banded, olive coils of a grass snake slide into view. Flickering its forked tongue, Snake parts the vegetation with its wedge-shaped head as its bright unblinking eyes strain to detect the slightest movement. Finding no trace of prey, the snake abandons its search, and with sinuous ease winds off back across the water, disappearing into a clump of rushes.

Encounters such as these, with Britain’s largest and most numerous snakes are surprisingly common. Widespread in England and Wales, though rare in Scotland and absent from Ireland, the grass snake prefers moist lowland areas and may often be seen sunning itself on the bank of a stream or swimming sinuously across a shallow pond.

Grass snakes will prey on lizards, nestling birds, mice and voles, but newts, tadpoles and frogs from the bulk of their diet. The grass snake tracks its prey by scent, for despite its unblinking, glassy stare, its eyes are not well developed and only much use for detecting movement. But with each flick of its forked tongue the snake literally tastes the air for traces of its next meal.

Lacking the venom of the adder, or the constricting coils of the smooth snake, the grass snake relies on stealth and a lighting quick strike to catch its prey, Once a frog or newt is in its grasp, the snake dislocates its lower jaw and then slowly inches first the upper and then the lower jaw over its victim until it is swallowed whole, often appearing as a conspicuous bulge in the snake’s elastic and muscular tube like body.

Wherever possible, the snake catches its prey head first. This minimizes the risk of the biter being bitten and makes the prey easier to swallow. Most victims then quickly drown in the snake’s copious saliva, before the digestive juices get to work.

Because the snake squanders none of its energy on keeping warm, a large meal can last it a week. But being cold blooded does have its disadvantages. In order to become active enough to hurt, the grass snake must first raise its body temperature – which it does by sunbathing.

On a midsummer’s morning when the dawn temperature is above the critical 15C, the grass snake will be active soon after sunrise, catching any unwary frog or newt and then sunbathing until the sun becomes too fierce around noon, when it will slither into the shade. But in cooler weather it must spend longer periods basking before it is fit for the chase. This reliance on the sun means that by the end of September it is forced to seek out a sheltered hideaway, such as an old rabbit burrow, where it can hibernate beyond the reach of winter frosts.

When the balmy fingers of spring reach down into the snake’s lair to wake it from its winter’s sleep, the snake emerges slothfully, and for the next week or two will spend every opportunity sunbathing. Once fully revived, the urge to mate drives the males off on the trail of the females which exude a powerful scent. Once a suitable mate is found the two snakes will bask together, sometime for days on end. Eventually the male will become aroused and begin sliding over and around the female. Flicking his tongue over her skin and thrusting his head into her coils he will attempt to make her unwind so that they can lie side by side and mate. After mating, but over the six week mating period from April to May, each snake may have several partners.

In mid-June the female starts looking for somewhere to lay her eggs. A compost heap, where the warmth generated by the rotting vegetation will nurture the sticky white, leathery eggs, older ones up to 40. But because ideal nest sites are few and far between, many females often lay in the same place – leading to a mass hatch and stories of plagues of snakes.

The young snakes are six inches long when they hatch but grow quickly, shedding their skin for the first of many moults when they are two or three weeks old. In their first year they will grow five inches, adding a further four inches in their second. By their year the male grass snakes will be around 20 inches and sexually mature. Females mature in their fourth year when they will be about 26 inches long, Growth then slows, and, once mature, the snake will start thickening rather than lengthening. An average female grows to 30 inches and a male to 26 inches.