AT A GLANCE
- Common Name: Eastern Slow Worm
- Scientific Name: Anguis colchica
- Category: Reptiles
- Subcategory: Lizards
- Range: Eastern Europe, the Baltic states, western and southern Russia, the Caucasus, and northern Iran
- Habitat Type: Damp deciduous and mixed woodlands, forest edges, meadows, overgrown gardens, railway verges, and damp scrublands
- IUCN Red List Status: Least Concern
- Lifespan: 20 to 35 years in the wild; captive individuals have lived over 50 years
- Diet: Carnivorous/Molluscivorous (specializes on slugs, earthworms, small snails, spiders, and soft-bodied insect larvae)
- Average Size/Weight: 35 to 50 cm in total length; 30 to 70 g in weight
- Key Defining Feature: Smooth, shiny, cylindrical legless lizard with metallic bronze-brown scales, blunt tail, and conspicuous turquoise-blue spots on mature males
Overview
The Eastern Slow Worm (Anguis colchica) is a fascinating, completely legless squamate lizard native to the cool, moist landscapes of Eastern Europe, the Caucasus, and western Asia. Historically lumped together with the Western Slow Worm (Anguis fragilis), rigorous genetic and morphological research established it as a distinct evolutionary species. Despite its superficial resemblance to a small snake, the slow worm is a true lizard, possessing movable eyelids, external ear openings, and the ability to shed its tail when attacked. A gentle, slow-moving inhabitant of compost heaps, damp woods, and hedgerows, it is a gardener’s best friend due to its insatiable appetite for pestiferous garden slugs.
Biology and Physical Characteristics
Anguis colchica possesses a cylindrical, serpent-like body with no external traces of limbs, covered in small, smooth, polished, highly polished overlapping scales supported by internal bony plates called osteoderms. The body coloration is a rich metallic golden-brown, bronze, or coppery-grey, with paler, yellowish sides. Adult males frequently develop striking, bright sky-blue or turquoise spots across their back and flanks, an ornamental feature far more prevalent and vivid in this eastern species than in western populations. Unlike snakes, slow worms can blink with fully functional eyelids, have notched rather than deeply forked tongues, and possess flexible, non-expandable jaws.
Behavior and Ecology
Slow worms are fossorial and crepuscular, spending long periods hidden beneath flat rocks, rotting logs, discarded corrugated iron sheets, or leaf litter where humidity remains high. They emerge during humid dusk or after warm summer rain showers to hunt, using their curved teeth to grasp slippery, mucus-coated slugs and earthworms before slowly swallowing them whole. Reproduction is ovoviviparous (viviparous): females retain developing embryos inside their bodies for three months, giving birth in late summer to 6 to 15 golden, translucent, free-living young wrapped in delicate membrane sacs that rupture immediately upon delivery.
Conservation and Human Impact
The Eastern Slow Worm is categorized as Least Concern on the IUCN Red List due to its expansive geographic distribution and stable overall numbers. It is legally protected from killing, injury, and trade under Appendix III of the Bern Convention and national wildlife legislation across most Eastern European nations. Local threats stem from urban expansion, intensive agriculture, the use of toxic molluscicides (slug pellets) that poison foraging lizards, and heavy predation by domestic and feral cats.
Interesting Factoid
Although completely legless and frequently mistaken for a snake, the slow worm can blink its eyes, possesses visible ear holes, and can drop its tail in self-defense—anatomical traits no snake in the world possesses.