Adder is a snake, member of the viper family. The adder has a relatively stout body for a snake and a short tail. The average male is 21 in. long, the female 2 ft — the record length is 2 ft 8 in. The head is flat, broadening behind the eyes to form an arrow-head shape. A The adder’s tongue looks menacing but is harmless. It is a smell-taste organ picking up particles from the air and withdrawing them for analysis in the mouth
The colour and body-markings vary considerably; adders are among the few snakes in which male and female are coloured differently. Generally the ground colour is a shade of brown, olive, grey or cream; but black varieties in which all patterning is obliterated are fairly common. The most characteristic marking is the dark zig-zag line down the back with a series of spots on either side; the head carries a pair of dark bands, often forming an X ora V.
It is often possible to distinguish the sex of an adder by its colour. Those which are cream, dirty yellow, silvery or pale grey, or light olive, with black markings, are usually males; females are red, reddish brown or gold, with darker red or brown markings. The throat of the male is black, or whitish with the scales spotted or edged with black; females have a yellowish-white chin sometimes tinged with red.
Distribution and habits
The adder ranges throughout Europe and across Asia to Sakhalin Island, north of Japan. In the British Isles it is absent from Ireland and the northern isles but is the only snake found in Scotland. It is usually to be seen in dry places such as sandy heaths. moors and the sunny slopes of hills where it often basks in the sun on hedge-banks, logs and piles of stones. It is, however, also found in damp situations.
Its tolerance of cold allows the adder to live as far Finland, within the Arctic Circle. It escapes cold weather by hibernation, which starts when the shade temperature falls below 9 C/49″ F. It emerges again when the air temperature rises above 8 C/46’F — even coming out on to snow — but a cold spell will send it in again. The duration of hibernation depends, therefore, on climate: in northern Europe it may last up to 275 days, whereas in the south it may be as little as 105 days. In Britain, adders usually hibernate for about 135 days in October-March, depending on the weather.
Unlike many other snakes adders do not burrow but seek out crevices and holes where they lie up for the winter. The depth at which they hibernate depends like duration, on the climate: in Britain the average depth is 10–12, but in Denmark, where winters are more severe, adders are found at depths of 4 ft.
Very often many adders will be found in one den, or hibernaculum. As many as 40 have been found coiled up together, along with a number of toads and lizards. This massing together is a method of preventing heat loss, but it is not known how the adders come to congregate in hibernacula, which are used year after year. It may be that they can detect the scent left from previous years.
It is uncertain whether adders are nocturnal or diurnal. Their eyes are typical of between nocturnal animals in that they are rich in the very sensitive rod cells: such eyes will see well at night, but during the day they need protection, and the adders slit pupils cud down the intensity of light. On the other hand, despite these adaptations, adders are often active during the day. Courtship and some feeding are definitely diurnal; the timing of the latter depends on how hungry the adder is.
The adder’s main prey is lizards, mice, voles and shrews. Young adders subsist at first on insects and worms. Larger victims are killed by a poisonous bite, the effects of which vary with the size of the prey. A lizard will be dead within a few minutes, or even within 30 seconds; but an adder’s bit is rarely fatal to humans.
The adder’s method of hunting is to follow its prey by scent, then poison it with a quick strike of the head. While the poison acts, the victim may have time to escape to cover, in which case the snake will wait for a while then follows to eat its dead prey.
Dance of the adders
The mating period is from the end of March to early May, though it has been known to last until autumn. In the north of Europe the summer is too short for the eggs to mature in one year, so breeding takes place in alternate years.
At the beginning of the breeding season, there is a good deal of territorial rivalry between males, culminating in the “dance of the adders”. Two males face each other with head erect and the forepart of the body held off the ground. They sway from side to side, then with bodies entwined each attempts to force the other to the ground by pushing and thrusting. They do not attempt to bite each other.
Finally one gives up and departs. The female, who is frequently waiting close at hand, will accept any victorious male, if she is ready, and a male will mate with any female. He crawls up behind her and loops his coils over her body, rubbing his chin (which has especially sensitive skin) on her back until he reaches the back of her neck, and mating take place.
Adders are ovoviviparous: that is, the eggs remain inside the mother’s body until they are fully developed, and the young are born coiled up in a membrane which is ruptured by their convulsive movements. They have an egg tooth, which in other animals is used to rupture the egg membranes, but in adders it is degenerate as they have no need of it, and the tooth is so situated that it is of no use for this purpose. It is shed a few days after birth.
The young are born in August or September and the number ranges from 5 to 20: 10-14 are most common, each measuring 6-8 inches in length. They are immediately capable of independent existence, but often they appear to stay with the mother.
Predators defy poison
Like most animals – even those well capable of defending themselves – adders are most likely to flee if confronted with danger, and they usually bite only if suddenly frightened. But, despite not having the excuse of self-defence, man is their chief enemy. However, the killing of adders on sight has not led to their decline, although nowadays increased urbanisation is destroying their habitat.
Undoubtedly many carnivores will take adders. Foxes and badgers will them, and they have been found in the stomachs of pike and eels. Surprisingly, perhaps, the hedgehog is a great adversary of adders: one reason is that it can tolerate large doses of venom without harm. Its method of killing is to bite the adder, then curl up leaving nothing but a palisade of spines for the snake to strike at. It repeats the process of biting and curling until the snake is dead, after which the hedgehog eats it.
A confusion of names
The Anglo-Saxon name for the adder was naedre, which became “a nadder” or “a nedder” in Middle English. Later the n was transported, so that we now have “an adder”. The alternative name viper comes from the Anglo-Saxon vipere or vipre, itself derived from the Latin vipera. This was a contraction of vivipara, from vivus (alive) and parere (to bring forth) – alluding to the animal’s method of reproduction. In general ‘viper’ was used to mean any venomous snake. There being only one such snake in England, viper and adder became synonymous for the one species (viper also being used to describe a venomous or spiteful person).
The two words have spread with the English language all over the world, being used not only for snakes of the genus Vipera. There are the near relatives such as the gaboon viper, more distant, like the pit vipers and mole vipers, and the death adder, which is not even in the viper family.