Snake identification key
Answer whatever you can — every question is optional and the list narrows as you go. Venomous species stay pinned to the top of the results for as long as they are still possible, because ruling those out is the point of the exercise.
Before anything else
- Back away and leave it alone. A snake that can see you leaving has no reason to bite. Most bites in the United States happen to people who picked up, cornered, or tried to kill a snake.
- Never handle a snake to identify it. Every identification on this site can be made from a photo or from several feet away.
- If someone is bitten, call emergency services now. Keep the limb still and below the heart, remove rings and watches, and go to hospital. Do not cut, suck, apply ice, or use a tourniquet — all of these make outcomes worse.
- Do not try to catch the snake for identification. A photo from a distance is enough, and hospitals treat symptoms rather than species.
In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.
1.Which state are you in?
optionalThe most powerful question here. Most states have only one or two venomous species, and several have none at all.
2.What were the markings like?
optionalJudge this from the back of the snake. Whether the pattern continues onto the belly is the single most useful thing to notice with a ringed snake.
3.How big was it?
optionalPeople consistently overestimate snake length, so this only narrows things roughly — neighbouring sizes stay on the list.
4.Where did you see it?
optionalHabitat rules out a surprising amount. A snake several feet up a tree is very unlikely to be a pit viper.
5.Did it do any of these?
optionalBehaviour is often more reliable than colour. Pick everything you actually saw — not what you think it might have done.
6.What colour was it?
optionalDeliberately last, and it never removes anything from the list. Snakes look completely different when wet, shedding, or seen in shade.
- Black-tailed RattlesnakeVenomousCrotalus molossus
- CopperheadVenomousAgkistrodon contortrix
- CottonmouthVenomousAgkistrodon piscivorus
- Eastern Coral SnakeVenomousMicrurus fulvius
- Eastern Diamondback RattlesnakeVenomousCrotalus adamanteus
- MassasaugaVenomousSistrurus catenatus
- Mojave RattlesnakeVenomousCrotalus scutulatus
- Prairie RattlesnakeVenomousCrotalus viridis
- Pygmy RattlesnakeVenomousSistrurus miliarius
- SidewinderVenomousCrotalus cerastes
- Sonoran Coral SnakeVenomousMicruroides euryxanthus
- Texas Coral SnakeVenomousMicrurus tener
- Timber RattlesnakeVenomousCrotalus horridus
- Western Diamondback RattlesnakeVenomousCrotalus atrox
- Western RattlesnakeVenomousCrotalus oreganus
- Banded Water SnakeHarmlessNerodia fasciata
- Brahminy BlindsnakeHarmlessIndotyphlops braminus
- CoachwhipHarmlessMasticophis flagellum
- Common Garter SnakeHarmlessThamnophis sirtalis
- Corn SnakeHarmlessPantherophis guttatus
- Dekay's BrownsnakeHarmlessStoreria dekayi
- Diamondback Water SnakeHarmlessNerodia rhombifer
- Eastern Hognose SnakeMildly venomousHeterodon platirhinos
- Eastern Indigo SnakeHarmlessDrymarchon couperi
- Eastern KingsnakeHarmlessLampropeltis getula
- Eastern Milk SnakeHarmlessLampropeltis triangulum
- Eastern RatsnakeHarmlessPantherophis alleghaniensis
- Eastern WormsnakeHarmlessCarphophis amoenus
- Gopher Snake / BullsnakeHarmlessPituophis catenifer
- North American RacerHarmlessColuber constrictor
- Northern Water SnakeHarmlessNerodia sipedon
- Plain-bellied Water SnakeHarmlessNerodia erythrogaster
- Red-bellied SnakeHarmlessStoreria occipitomaculata
- Ring-necked SnakeHarmlessDiadophis punctatus
- Rough Green SnakeHarmlessOpheodrys aestivus
- Scarlet KingsnakeHarmlessLampropeltis elapsoides
- Speckled KingsnakeHarmlessLampropeltis holbrooki
- Western RatsnakeHarmlessPantherophis obsoletus