Often, an Academy biologist or docent will bring out one of the snakes for guests to see and touch. There are many common questions when a guest comes up close and personal with a Ball Python or Boa Constrictor. The most common question asked is – is this snake poisonous? And it is not only children asking if the snake is poisonous but adults as well. Many people think snakes are poisonous animals, however, snakes cannot actually be poisonous.

Although both poison and venom are toxic, they differ in the method of delivery. Poison is only effective if ingested orally or absorbed; venom, on the other hand, is always injected. So snakes are not poisonous, but they can be venomous.

There are many telltale indications that an animal is poisonous or venomous. Toxic animals usually advertise by color, behavior, or sound. Take, for example, the Poison Dart Frog – it secretes poison through its skin. These frogs are brightly colored, which acts as a visual deterrent for predators. Rattlesnakes, on the other hand, will signal their toxicity through threatening behavior and sound. When threatened, rattlesnakes will ready themselves in a striking pose and rattle their tails. Additionally, rattlesnake venom is kept in two venom sacs in the snake’s mouth, which alters the shape of the mouth. Non-venomous snakes have a circular mouths while venomous snakes, like rattlesnakes, have triangular mouths.

Venom is a highly effective survival tool for many different species. Venomous animals are found throughout the world and are most often very distinctive. Along with being able to defend themselves from many predators, venomous animals are also able to take down prey which are larger and faster than themselves.

Being venomous is so advantageous in the animal world in that many animals will fake it. Known as mimicry, the mimic will take on the coloration or characteristic of the model. Both the venomous Eastern coral snake and non-venomous scarlet king snake are banded red, yellow, and black; however; the order of the colors differs just slightly. Though both are striking in color, only the coral snake is toxic.

So in many instances color, behavior, or sound can let you know if an animal is poisonous or venomous. You can never be one hundred percent sure, however, as toxicity is an adaptation that many other species will copycat. When in nature it is better to be safe and keep a distance. For more information about toxic animals, to take a venom quiz, or to learn about different toxic species visit http://www.calacademy.org/exhibits/venoms/html/venoms_101.html#.

But back to the original question – is this snake poisonous? No. Is it venomous? Again the answer is no. We do not have any venomous programming animals. The most common type of programming snake we have at the Academy is a constrictor. A constrictor will squeeze its prey causing death through asphyxia or cardiac arrest. The majority of constrictors are non-venomous.

Cat Aboudara is the Special Projects Manager at California Academy of Sciences and works in the public programs division. The Academy is a wonderful fit for her because of her curiosity about the natural world and her experience in working with native California wildlife.

latitude: 37.7819, longitude: -122.404

Snakes are not Poisonous 12 December,2007Cat

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  • leilanami

    There is a species of poisonous snake in Asia and they have found that some populations of Thamnophis spp. have toxic livers and would be considered poisonous if eaten. As a rule of thumb, yes, you can correct them to say venomous, but you shouldn’t say there couldn’t be poisonous snakes as that is factually incorrect.

    • ariyana

      really what app did you go to find out?

      • leilanami

        I don’t use apps. I’m a biologist with research in herpetology and arachnology.

  • ariyana

    i agree snakes are not poisonos plus is a python dangouros?

  • ariyana

    really how did you found that there is a poisonous snake in asia?

  • Rayvyn007

    The person who posted this is dead wrong. Snakes that produce venom are poisonous snakes. It’s grammatically correct. Poisonous means anything that is or can produce a toxin that means animals too and that includes snakes. The Oxford English Dictionary says it’s grammatically correct to say poisonous OR venomous snakes. Poison does not have to be ingested. Poison can be injected via a needle or fang. Shell fish poison has been injected to kill people. I don’t know where people get their English teaching from these days. This is article is posted by a blogger and is not a fact.

    • a_ford

      The key is how THE ANIMAL ITSELF delivers the toxin. If the animal injects it, it’s venomous. If you have to ingest the toxin, it’s a poison. Since shellfish and poison dart frogs don’t carry around syringes to inject their poison into people, your distinction doesn’t exist unless artificially created BY A HUMAN. I don’t care if you like it or not, snakes are venomous, not poisonous, as are spiders and scorpions, because they inject venom into the bloodstream, and that includes species of cobras that squirt venom into the eyes of offending predators — the venom enters the predator’s bloodstream through thinly-walled tiny veins in the eyeball. If squirted on your skin, it’s harmless. In short, it’s silly to say that if you inject poison into someone that it’s a venom. Does that go for cyanide or strychnine?

  • Michael Adonis

    There ARE poisonous snakes. The Tiger Keelback of Asia sequesters toxins (poison) from the toads it eats and stores the toxin in a nuchal gland. This snake can expel the poison from these glands to deter predators. The keelback is also venomous, delivering venom through rear enlarged fangs. The common gartersnakes residing in the Pacific Northwest consumes highly poisonous newts, storing the poison in it’s liver. Animals that feed on the internal organs of these snakes get poisoned. To learn more about wild snakes – facebook.com/groups/snakeED



Cathleen (Cat) is the former Special Projects Manager at California Academy of Sciences and worked in the public programs division.
Before working at the Academy, Cat got her start as an intern at Lindsay Wildlife Museum for four years and worked with animals ranging from snakes and hawks to foxes and bobcats. She has a deep curiosity about the natural world and native California wildlife.

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