How are lizards different from snakes?

Lizards and snakes are both reptiles belonging to the order Squamata, but they are distinguished by several key physical traits.1

Primary Differences

• Limbs: Most lizards possess legs, whereas snakes are a specialized group of limbless lizards that lost their limbs as they adapted to burrowing habits.12
• Ears: Lizards typically have external ear openings, while snakes lack external ear openings entirely.12
• Eyelids: Most lizards have movable eyelids, a feature generally absent in snakes.1
• Skull Structure: While both groups have kinetic skulls, snakes possess the most highly specialized kinetic skulls among vertebrates. Their skulls feature a highly mobile quadrate bone and upper jaws capable of rotating and moving independently, which allows them to swallow prey whole.3

It is important to note that these distinctions are not universal. Some traditional lizard species have undergone limb degeneration or lost their external ear openings and movable eyelids over time. Despite these differences, both animals share common behaviors, such as using their tongues to pick up scent molecules for Jacobson’s organ and relying on their environment to regulate body temperature.142