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Head of slow worm

Head of slow worm

Slow worms on wall

Slow worm emerging from vegetation

Slow worm head emerging

Slow worm coiled up

Slow worm
Anguis fragilis

Slow worms look superficially like snakes, but are actually legless lizards. One way to identify them is that unlike snakes, lizards (and therefore slow worms) have eyelids.

Length: 30-50cm.

Physical Description
Slow worms have smooth and shiny snake-like bodies with an indistinct head, and can be distinguished from snakes by the presence of eyelids. Males vary in colour from grey, to light brown or bronze with a pale belly. Females are typically browner than the males, and have darker brown flanks, a dark belly and a black stripe running along the back. Both sexes, but more commonly males, will sometimes have blue spots on the body. This blue colouration is more common in coastal or island populations, and may vary over the year. It does not usually occur until an animal is at least three years old.

Slow worms are thought to be the most commonly distributed of all European reptiles, although they are absent from the far north, Ireland and southern Spain. They are also found in north west Asia. In Britain, they are commonest in Wales and the south west of England.

Slow worms prefer humid habitats, including grassy meadows, gardens, farmland, woodland margins and open fields. They can also be found in rural gardens and commonly fall prey to domestic cats.

They emerge from hiding places to hunt at dusk or after rainfall. Slow worms are not particularly speedy reptiles and feed on slow-moving prey such as slugs, snails, spiders, insects and earthworms.

They are not often seen basking in the sun and prefer to hide under rocks and logs. If caught by a predator, they have the ability to lose their tails, but the tail never fully grows back. They hibernate from October to February/March under piles of leaves, within tree roots and in crevices of banks. They hibernate both communally and solitarily, and sometimes share hibernating sites with other reptiles. They sometimes burrow in soft substrates so that just their heads are visible.

Slow worms start to mate around April and May, but cannot actually conceive until June when the females’ eggs pass into their oviducts. Males will fight with each other for possession of females. Females may pair with several males throughout the breeding season. An average of 6-12 young (although as many as 26 is possible) are born after a gestation period of 3-5 months. They are encased in a transparent membrane at birth, which they immediately break free of.

Conservation status
Slow worms are protected under the Wildlife and Countryside Act 1981 from being killed, injured or sold and are less common than they used to be.

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