Even though they are actually lizards, slow-worms are frequently confused for snakes. In contrast to snakes, they have eyelids, their tongue is flat and forked, and they may lower their tails to get away from a potential threat. Shiny exteriors are a distinguishing feature of slow-worms. The males have a brownish-gray coloration, while the females are brown throughout but have darker sides. A faint stripe can be seen running down the back of certain females. Young slow-worms typically measure about 4 centimeters in length and have a very slender body. Juveniles have black bellies and gold or silver dorsal sides, and they may or may not have a stripe that runs the length of their body.
Slow-worms, in contrast to most other British reptiles, do not prefer to sunbathe in open areas; rather, they prefer to hide in compost heaps or behind logs. Prey that moves slowly, such as tiny slugs, is the primary source of nutrition for slow-worms. Female slow-worms, much like female common lizards, incubate their eggs inside and 'give birth' during the late summer months.