Slow Worm (Anguis fragilis)

ReptileLegless LizardEurope

Overview

The slow worm (Anguis fragilis) is one of the most commonly misidentified animals in Europe. It is neither a worm nor a snake: it is a legless lizard, and its smooth, glossy, uniformly coloured body simply lacks limbs.

Two features settle the identification immediately. A slow worm has movable eyelids and can blink — snakes cannot, since their eyes are covered by a fixed transparent scale — and it has a fleshy, notched tongue rather than the deeply forked tongue of a snake.

Its scientific name means 'fragile snake', a reference to the third giveaway: like many lizards, a slow worm can shed its tail when seized, leaving the still-twitching tail behind while it escapes.

Habitat & Range

Slow worms are widespread across Europe and into western Asia, in grassland, heath, woodland edges, hedgerows, railway embankments, allotments and gardens. They favour places with dense low vegetation, warmth and cover, and spend much of their time hidden — under logs, stones, compost heaps and corrugated sheets — rather than basking openly like many lizards.

Diet

Slow worms feed largely on slow-moving soft-bodied invertebrates, above all slugs, along with snails, earthworms, insect larvae and spiders. Their small, slightly backward-curved teeth are suited to gripping soft, slippery prey. That diet is why they are so welcome in gardens and allotments.

Behavior

Slow worms are secretive and semi-fossorial, spending much time underground or beneath cover, and often thermoregulate by lying under sun-warmed objects rather than in the open. They are long-lived for a small reptile. Unusually, slow worms give birth to live young rather than laying eggs, and they hibernate through the winter, sometimes communally, in burrows and other sheltered places.

Human Interaction & Conservation

Slow worms are harmless to people and beneficial to gardeners because of their appetite for slugs, but they are frequently killed through mistaken identity as snakes, and are vulnerable to cats, strimmers and habitat tidying. In several countries, including the UK, they are legally protected. Providing undisturbed cover such as log piles, compost heaps and rough corners supports them. This profile offers no handling or keeping guidance; wild reptiles should be left undisturbed and questions referred to local wildlife authorities. Verify current status at the IUCN Red List.