Slow Worm Fact File
The slow worm (also known as the blind worm) is a species of legless lizard found in Europe and western Asia. They have lost their limbs and have smooth scales with both of these adaptations helping them to burrow under the ground.
They hunt for a range of invertebrates which are seized with the help of their curved teeth.
When threatened they have the ability to shed their tail.
Slow worms are a species of legless lizard. Their body is covered with smooth scales which assist them with burrowing. It has a uniform cylindrical shape lacking the narrowing of the neck which differentiates them from snakes.
These animals are often confused for snakes but they can be distinguished due to their eyelid. Slow worms have a moveable eyelid whereas snakes are not able to blink.
Young individuals are bold in their coloration and have a central stripe running down their body. As adults the females keep this dark-colored stripe but males tend to be a flat coppery brown or grey across their body.
In parts of their range, especially the east the males have blue spots on their face.
The tongue of the slow worm is broad and flat. At the end a small notch divides the tongue in to two parts but it is not the deep fork seen in snakes.
An adult slow worm will measure 30-50cm (12-20in) long with an average weight of 20-100g (0.7-3.52oz).
Slow worms are carnivores which feed on invertebrates.
The teeth of slow worms curve backwards to help secure their food.
Slow worms are native to Europe, North-west Africa and Western Asia. Here they can be found in the following countries – Albania; Andorra; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czechia; Denmark; Estonia; Finland; France; Georgia; Germany; Greece; Hungary; Iran, Islamic Republic of; Italy; Kazakhstan; Latvia; Lithuania; Luxembourg; Moldova; Montenegro; Netherlands; North Macedonia; Norway; Poland; Portugal; Romania; Russia; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine and the United Kingdom.
They make their home in grassy meadows, woodland glades, heathland, forest clearings or forests.
Slow worms have shown the ability to live alongside humans in their backyards or in parkland.
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Their mating season will begin in around April. During this period males become highly aggressive to one another.
The courtship period for these animals can last for as long as 10 hours.
Following a successful mating the eggs are incubated inside the female. These will hatch and the young spend a short period living inside the female and feeding off their yolk.
She will then give birth to between 6 and 12 live young after a 3 to 5 month gestation period. The entire incubation period is undertaken inside the body.
Males mature first between 3 and 4 years old followed by the females between 4 and 5 years old.
From October to March the slow worms will hibernate. Males emerge from this slumber before the females. In norther parts of their range where they undertake the longest hibernation they may spend as much of half of their life in this state.
They may also spend the hottest parts of summer underground.
Most of their activity takes place at dusk though they may occasionally emerge during the day to bask. When at rest they burrow in to loose sand or under a rock.
To warm up the slow worm will sit on a rock or log.
Slow worms will regularly shed their skin. This is done in multiple pieces unlike snakes which shed their skin in one piece.
Predators and Threats
Predators of the slow worm include domestic cats, birds such as pheasants, hedgehogs, European badgers and snakes such as adders.
When threatened by a predator the slow worm has the ability to shed its tail. This allows them to escape with the important parts of their body. The tail can continue to move for up to 15 minutes helping to distract the predator.
The tail will regenerate but this process is slow leaving them looking short in appearance for long periods. This new tail will differ in color and internal structure to the original.
They may also defecate when captured which produces a foul smell which can put off predators.
Humans have affected slow worms though habitat loss caused by urbanization and fires. They may also be killed by vehicle strikes.
With a lifespan of up to 54 years the slow worm is a candidate for being one of the world's longest lived lizards.
Slow worms may also be known as blind worms.
PlayMistyForMe at Luxembourgish Wikipedia, CC BY-SA 1.0 <https://creativecommons.org/licenses/by-sa/1.0>, via Wikimedia Commons
Petar Milošević, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
© Hans Hillewaert / CC BY-SA 4.0
Iwona Kałuzińska, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
Burnie, D., 2011. Animal. 3rd ed. London: DK
Jackson, T. and Chinery, M., 2005. Animals of Africa & Europe. London: Southwater.
Wildlifetrusts.org. 2021. Slow worm | The Wildlife Trusts. [online] Available at: <https://www.wildlifetrusts.org/wildlife-explorer/reptiles/slow-worm> [Accessed 9 May 2021].
Aram Agasyan, Aziz Avci, Boris Tuniyev, Jelka Crnobrnja Isailovic, Petros Lymberakis, Claes Andrén, Dan Cogalniceanu, John Wilkinson, Natalia Ananjeva, Nazan Üzüm, Nikolai Orlov, Richard Podloucky, Sako Tuniyev, Uğur Kaya, Hans Konrad Nettmann, Wolfgang Böhme, Bogoljub Sterijovski, Milan Vogrin, Claudia Corti, Valentin Pérez Mellado, Paulo Sá-Sousa, Marc Cheylan, Juan Pleguezuelos, Varol Tok, Roberto Sindaco, Bartosz Borczyk, Benedikt Schmidt. 2009. Anguis fragilis. The IUCN Red List of Threatened Species 2009: e.T157249A5060016. Downloaded on 09 May 2021.
BTO – British Trust for Ornithology. 2021. Slow-worm. [online] Available at: <https://www.bto.org/our-science/projects/gbw/gardens-wildlife/garden-reptiles-amphibians/a-z-reptiles-amphibians/slow-worm> [Accessed 10 May 2021].
Shortridge, A. 2019. "Anguis fragilis" (On-line), Animal Diversity Web. Accessed May 09, 2021 at https://animaldiversity.org/accounts/Anguis_fragilis/
Woodland Trust. 2021. [online] Available at: <https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/animals/reptiles-and-amphibians/slow-worm/> [Accessed 10 May 2021].
Nhm.ac.uk. 2021. Slow worms: Britain's most unusual lizards. [online] Available at: <https://www.nhm.ac.uk/discover/slow-worms-most-unusual-lizards-in-britain.html> [Accessed 10 May 2021].
New Forest National Park Authority. 2021. Slow-worm – New Forest National Park Authority. [online] Available at: <https://www.newforestnpa.gov.uk/discover/wildlife/reptiles/slow-worm/> [Accessed 10 May 2021].