These charming, little legless lizards are often found in gardens or allotments, half hidden under stones or log piles.  Slow worms are shy and secretive, and unlike other lizards, they don’t bask out in the open, so they are not often seen, although they may well be present in your garden.  Slow worms are carnivorous and feed mainly on slugs, small snails, insects and worms. Their natural habitat is grassland and woodland and they are distributed all across Europe.

 Slow worms (also known as blind worms or glass snakes) are harmless. If you pick them up they may try to take a bite but as their teeth don’t protrude past their gums the bite will be no more than a gumming of your hand. Being lizards their jaws are not able to dislocate and extend in the manner of snakes. Unlike snakes slow worms have eyelids and ear holes and they can drop their tales. If you are ever lucky enough to have the opportunity of observing a slow worm for any length of time you will also notice that the slow worm’s back bone isn’t nearly as flexible as a snake’s and even without legs, their movements are rather lizard-like.

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The slow-worm is ovi-viviparous, meaning that the young hatch out of their eggs while still inside their mother and they emerge still encased in an egg membrane that breaks soon after birth. The usual number of babies is about 8 to 10 and they are very small, measuring only about 80mm long when they are born.  The young become sexually active at about 5 years of age and reach  full size – about 45cm long - at about 8 years and they can live for up to 30 years in the wild.  Distinguishing between males and females is relatively easy. Males tend to be grey to coppery brown while females are a glossy copper with dark flanks and a back stripe.

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Unlike snakes and other British lizards, slow worms don’t enjoy the heat of high summer, but as they are exothermic they do need to be in a relatively open habitat that will allow them to bask, but not be exposed.  They have very little in the way of protection; they don’t have speed or sharp teeth. The only thing they have at their disposal (so to speak) is the ability to drop their tales when they are threatened. This allows them to escape and provides a bit of a distraction as the discarded tail wiggles on the ground. A new tail grows back with within about two weeks, but it grows with a cartilaginous skeleton rather than a new bone and the new tail won’t be as long as before, nor will it have the ability to regrow again.

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Late summer and early autumn are busy times in the life of a slow worm. The young are born at this time of year and the young and the adults need to  find enough food to  put on sufficient body fat to see them through their 5 months of hibernation.   Compost heaps are often chosen as hibernaculums because of the raised temperature in the heaps, but slow worms can also be found holed up underground, in deep litter and under log piles. Temperatures in the hibernaculum must not drop below freezing or the slow worm will die. They emerge from their winter protection  in late February or early March.

 

• Slow worms live for a long time. The record for the longest life span is 54 years for a specimen that lived in Copenhagen zoo.

• As with all wildlife slow worms benefit from gardens not being too tidy and will seek out wild areas like areas of long grass, bramble patches or piles of logs or stones.   A sheet of rigid black plastic or corrugated tin in a quiet, sunny spot will make a wonderful hide-away.

• Compared to other lizards, slow worms are indeed quite slow and are frequently predated by cats, snakes, hedgehogs, badgers and birds.

• As slow worms often hibernate in compost heaps it is a good idea to leave turning the heap until the weather warms properly in April or May.