The adder (Vipera berus) is an extremely widespread reptile, and is the UK’s only venomous snake. As a result of its venomous bite, the adder is a much-maligned species in most of its range, with a wealth of folklore surrounding it. However, despite the public perception of this snake, it is generally a shy, timid and non-aggressive species. A stocky snake, the adder is easily identified by the dark zigzag line passing along the back bordered by rows of spots. A dark mark which takes the form of an 'X', 'V' or 'H' is located on the rear of the angular head and the pupil is vertical. Males are greyish, whitish, pale yellow or cream in colour with very dark contrasting markings, whereas females are typically a brownish or reddish colour with brown markings. Females also tend to be longer and wider than males, and have shorter tails. Male and female juveniles are reddish in colour. In all cases, the belly is grey, greyish-brown or bluish, and the throat is dirty yellow or white. Completely black (melanistic) adders arise quite frequently.
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