Yes, snakes are cold-blooded vertebrates classified as reptiles. They share fundamental reptilian traits, including scaly skin, lungs for breathing air, and an inability to internally regulate their body temperature, meaning they rely on their environment to stay warm or cool. [1, 2]
Snakes belong to the order Squamata, which also includes all lizards. In fact, evolutionary biologists classify snakes as specialized descendants of four-legged lizards that evolved to lose their legs over 150 million years ago. While some people mistakenly group legless lizards and snakes together, you can tell them apart because true snakes do not have eyelids or external ear openings. [1, 2, 3, 4, 5]