Snakes have no legs. The most common way snakes move is serpentine movement: the snake bends its body in a series of curves and pushes against surfaces. In rectilinear movement a snake moves forward in a straight line. Snakes slither partly because of friction from their belly scales. As of June 2009, a study from New York University and Georgia Tech had found that the scales are oriented so a snake resists sliding toward its tail and flanks. That gives it a preferred direction, like skis or ice skates, where sliding forward takes less work than sideways.
Snakes have no outer ears, but they do have a complete inner ear. As of May 2008, scientists had reported how it works: when a snake rests its head on the ground, vibrations shake the two sides of the lower jaw, and a chain of bones passes them to the inner ear, much like the tiny bones in your middle ear. Snakes can detect vibrations between 50 and 1,000 hertz, while people hear between 20 and 20,000 hertz, so a snake senses a much narrower range of vibrations than we hear.
A snake's sharpest sense is smell. Jacobson's organs are two small organs in the roof of a snake's mouth, and each opens to the mouth through a tiny hole in the palate. A snake flicks its forked tongue to pick up chemicals from the air, the ground or the water. After a flick, the tongue goes back into its mouth and fits into the Jacobson's organ, which sends signals to the same part of the brain as the nose. A snake's two tongue tips each deliver chemicals to their own Jacobson's organ, so the brain can compare the two sides, as your two ears let you tell where a sound comes from.
Some snakes have heat-sensing pits on the sides of the head that sense the warmth given off by warm-blooded prey. A snake's pit organ, which sits between the eye and the nostril in rattlesnakes, can sense infrared radiation, which is heat. The pit gives the snake a picture of its surroundings made from infrared radiation, a thermal image. Reticulated pythons have heat pits too. As of November 2026, University of Houston researchers reported in 2020 that cells in the pit organ membrane may work as a pyroelectric material, turning heat from warmer animals into electrical signals.
A snake's color helps it hide, and a green tree python's green color blends in with the leaves where it lives. Many snakes have plain pale bellies. This countershading helps them blend in, because the paler underside matches the light from above, so the snake looks one even color. When a harmless animal copies a dangerous-looking one, scientists call it Batesian mimicry. Scarlet kingsnakes and scarlet snakes copy the coral snake and gain protection by looking dangerous to predators. Snakes have predators too: birds, mammals and other snakes eat snakes, especially young ones.
A snake's mouth bones are loosely attached to each other and to the skull, and teeth that face inward trap prey once it is in the mouth. Together these let a snake swallow animals bigger than its head. After a big meal a snake does not need to eat again for a long time, and Burmese pythons can go four to six weeks between meals. Snakes that eat rarely, such as Burmese pythons, let their intestines shrink while fasting. After a big meal the intestine grows back very fast, and researchers study how. As of May 2025, a University of the Witwatersrand study had asked how much snakes can eat when rodents boom. Captive puff adders given unlimited food ate about 12 times their upkeep needs for long stretches, and they can also fast for over two years.
As of August 2012, scientists tracked wild snakes with radio telemetry: a small transmitter inside the snake sends a signal at its own frequency, and a researcher uses an antenna and receiver to find it, and because collars do not fit snakes, a vet implants the transmitter in the body cavity. As of April 2019, scientists used the Judas technique to study Burmese pythons that hide well in dense Everglades wetlands. They implant a radio transmitter in an adult python and release it. During the winter breeding season the tagged snake goes to find a mate, which leads researchers to other pythons, including large egg-bearing females. A wild snake is best left alone: it will usually go its own way. If one is near a home, a grown-up can call animal control.
Scientists think snakes evolved from lizards more than 100 million years ago, though the fossil record is thin. As of May 2015, a Yale team had built a family tree of living and extinct snakes from snake genomes, modern anatomy and fossils. It suggested the first snakes lived on land, not in the sea, that they were night-time stealth hunters of forests in the Southern Hemisphere, and that they still had tiny hind limbs with ankles and toes. As of February 2024, a study compared nearly 1,000 snake and lizard species, using partial genomes and stomach-content records from over 60,000 museum specimens. It found snakes evolved up to three times faster than lizards, which may explain why snakes became so varied.
Words to know
- friction: rubbing grip
- countershading: pale underside
- mimicry: copying looks
- pyroelectric: heat-to-electricity
- telemetry: remote tracking
