Reptiles
Glass Lizard
Ophisaurus · also called glass lizard, glass snake, jointed snake, legless lizard
The glass lizard is a lizard doing an almost perfect impression of a snake — and getting killed for it by people with a shovel. Look closely and the disguise falls apart: it blinks, it has ear holes, and its stiff body is nothing like a snake’s. Grab it and it does something no snake does — its tail shatters into pieces.
Overview
Glass lizards (genus Ophisaurus) are legless lizards found in North America, North Africa, southern Europe, and Asia, in loose soil, leaf litter, and dense grass. The largest reach 1–1.2 m, but two-thirds of that is tail. They eat insects, snails, worms, small reptiles, and eggs, swallowed whole because their jaw does not unhinge like a snake’s.
Not a snake
Glass lizards have movable eyelids, external ear openings, a fused lower jaw, a stiff bony-scaled body, and a fold-out groove of soft skin down each flank — all things snakes lack. Leglessness evolved here independently of snakes.
The shattering tail
The tail is more than half the total length and breaks apart very easily — often into several thrashing pieces — along preformed fracture lines, distracting a predator while the lizard escapes. It regrows slowly as a shorter, cartilage-cored stub that never matches the original.
Status
Glass lizards are Least Concern and generally common, but are constantly killed by people who mistake them for snakes, and by mowing and traffic.
Glass Lizard: common questions
Is a glass lizard a snake or a lizard?
It is a lizard, despite looking almost exactly like a snake. Glass lizards belong to the family Anguidae and evolved their legless, elongated body independently of true snakes; leglessness has arisen dozens of times among lizards. The features that give it away are all things snakes lack — glass lizards have movable eyelids and can blink, they have visible external ear openings behind the eye, their lower jaw is fused at the front so it cannot spread its mouth around large prey, and their body is stiff and covered in bony-reinforced scales rather than the smooth flexible scales of a snake. They also have a long groove of soft, fold-out skin running down each flank, which snakes do not.
Why is it called a "glass" lizard or "glass snake"?
Because of the way it seems to shatter. The glass lizard has an exceptionally long, fragile tail, more than half its total length, that breaks off extremely readily when the animal is grabbed, struck, or even handled roughly, and it often does not break cleanly at one point but fractures into two, three, or more writhing pieces. To someone seeing this for the first time it can look as though the "snake" has broken like glass. The pieces are just tail, and the twitching distracts the predator while the front half of the lizard crawls away. The folklore claim that the pieces later crawl back together and rejoin is not true.
Does the tail grow back?
Partly, and never as good as the original. Like many lizards, a glass lizard can regenerate a lost tail, but the replacement grows slowly over many months, is supported by a rod of cartilage instead of vertebrae, is usually shorter, darker, and differently patterned, and often has a blunt or irregular tip. A lizard can only regrow the tail from the point of the break, so an animal that lost most of its tail near the base stays dramatically shortened. Losing the tail is also costly beyond appearance — the tail stores fat, so a tail-less glass lizard has lost energy reserves and may breed less successfully the following season.
Are glass lizards dangerous, and can you keep one?
They are completely harmless to people. Glass lizards have no venom, and although a large one can give a firm pinch, its fused jaw and modest size mean the bite is trivial. They are shy and their instinct is to flee or drop the tail. They are kept as pets, particularly the eastern and slender glass lizards, and can be long-lived and personable, but they need a long enclosure with a deep, dry substrate to burrow into, hiding places, and a varied diet of insects and other invertebrates, and they must be handled gently and supported fully because a startled glass lizard will jettison its tail. Wild-caught animals are still common in the trade, so captive-bred stock is preferable.