Legless Lizards Are Not Snakes

Legless lizards are real lizards that evolved without useful legs and can often be told from snakes by features like eyelids, ear openings, and their long tails.

Biology

Details

A long, snake-shaped reptile is not always a snake. Legless lizards are lizards that have evolved to lose their limbs or reduce them until they no longer help with movement. This snake-like body shape has appeared independently in several different lizard groups, making leglessness a striking example of similar body forms evolving more than once. Some legless lizards can be separated from snakes by visible features such as movable eyelids and external ear openings. Their body shape can also provide a clue: many have a relatively short body followed by a long tail, while snakes generally have a long body and a shorter tail. Other differences can involve belly scales, tongue shape, and internal anatomy. The details are not identical across every species, so no single visual rule works for every limbless reptile. The broader point is that losing legs did not turn these animals into snakes. They remained part of the lizard side of reptile evolution, with several unrelated lizard groups arriving at a similar limbless body plan.

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