Forked tonguePicks up scent particles from the air and ground. It carries them to an organ in the mouth. The fork tells the snake which way a smell is coming from.
Dorsal scalesThe scales covering the back and sides. A snake's skin is smooth and dry, not slimy.
RattleA chain of hollow, interlocking keratin segments at a rattlesnake's tail tip. They buzz as a warning when shaken.
Ventral scalesThe wide, oblong scales across the belly. They grip the ground as the snake moves.
The head: 6 4
SpectacleA clear scale over the eye, in place of an eyelid. It stays permanently closed. It is also called the brille, and is shed with the old skin.
NostrilThe nostril, near the tip of the snout.
Heat pitA heat-sensing pit between the nostril and the eye. It is found on pit vipers such as rattlesnakes and lets them find warm prey.
FangA hollow fang that delivers venom when a venomous snake bites. Most snakes are not venomous.
Underneath: 3 2
VentThe opening under the body, covered by the anal plate. Here the belly ends and the tail begins. It leads to the cloaca.
Subcaudal scalesThe smaller scales under the tail, behind the vent.
How this list was compiled: Read 2026-09-27. (1) Wikipedia, Snake, https://en.wikipedia.org/wiki/Snake : snakes lack eyelids and external ears and have a forked tongue, which gathers scent particles and carries them to the vomeronasal organ, the fork giving direction; the eyelids are transparent spectacle scales, permanently closed; pit vipers have heat-sensing pits between the nostril and eye; venom delivered through hollow or grooved fangs; most species are not venomous; the skin is covered in scales and is smooth and dry; belly scales grip surfaces; the cloaca. (2) Wikipedia, Snake scale, https://en.wikipedia.org/wiki/Snake_scale : the ventral (belly) scales are large and oblong; dorsal scales; subcaudal scales under the tail; the anal plate; the brille or spectacle, shed with the skin. (3) Wikipedia, Rattlesnake, https://en.wikipedia.org/wiki/Rattlesnake : the rattle is a series of hollow, interlocked segments of keratin at the tail tip, a warning to predators; heat-sensing pits. Licence: own work
The drawing: Drawn for this site on 2026-10-05 by script. Own work, laid out by eye, nothing traced. The forms were checked against three public domain pictures on Wikimedia Commons: Head Scales of Crotalus and Sistrurus (Samuel Garman and Leopold Trouvelot, 1883), Crotalus atrox USFWS (Gary Stolz, US Fish and Wildlife Service) and the rattlesnake rattle figure of the Encyclopaedia Britannica (1911). Licence: own work
How it works
These are the parts of a snake on a rattlesnake: its head close up with the mouth open, the whole snake from above, then its underside. Start with the 5 main parts.
Read the full guide
The head
A snake has no moving eyelids: a clear spectacle scale covers each eye. The forked tongue picks up smells and tells the snake which way they come from. Rattlesnakes also have a heat pit between the nostril and eye.
Body and underside
Dorsal scales cover the back. Underneath, wide ventral scales grip the ground. The vent marks where the tail begins, and a rattlesnake's tail ends in the rattle.
Look underneath to find where the tail starts: the wide belly scales stop at the vent, and smaller subcaudal scales carry on under the tail.
Questions and answers
Why do snakes flick their tongues?
To smell. The forked tongue picks up scent particles from the air and ground and carries them to a smelling organ in the mouth. The two tips help tell which way a smell comes from.
Do snakes have eyelids?
No. Each eye is covered by a clear scale called the spectacle, or brille, which stays closed and is shed with the old skin.
What is a rattlesnake's rattle made of?
Keratin, the same material as fingernails, in a chain of hollow segments that knock together as a warning when the tail shakes.