Venom or Poison?
What is the difference?
Often the terms “poisonous” and “venomous” are used interchangeably depending on where you are in the world and what nature documentary you happen to be watching. However, when it comes down to it, poison and venom are biologically different.
In terms of function, poison is a defense mechanism. Plants and animals that are poisonous sometimes broadcast their toxicity with bright colours, spines or dramatic displays, telling a would-be predator to “Back off…or else you might regret eating me”. Some animals like monarch butterflies and caterpillars get their poison from the plants that they eat, like milkweed, while others like toads produce it themselves in special glands.
Poison must be absorbed through an epidermal tissue, meaning one can inhale (breath in poison such as poisonous gasses), one can eat/drink poison, or one can absorb poisons by touching them, such as with plants like poison ivy.
Venom on the other hand, is primarily a digestive enzyme, but it can also function as a defense mechanism. Most animals that are venomous like snakes, scorpions and spiders, use their venom to kill and pre-digest their food. And like poisonous animals and plants, some venomous ones use bright colours and displays to warn predators of what they are.
The difference between poison and venom is also that venom needs to be injected into the body, usually into the blood or subcutaneously (under the skin). It does not absorb well, and technically (although this is ill advised) one can drink venom and be completely unharmed, as long as there were no cuts in your mouth or tears in your digestive tract. Animals with venom have stingers, barbs or fangs for the purpose of injecting their venom.
The fact that so many plants and animals have evolved to be toxic is interesting because it means that there are predators that have co-evolved along side and have figured out some strategies to deal with toxins or that are completely immune. Elephants and tapirs both consume massive amounts of vegetation a day, and to ensure that they don’t ever eat “lethal” doses of poisons from the plants they eat, they browse on several differently types of plants throughout the day, instead of just eating one kind. For dessert they eat clay to absorb the poisons and toxins inside their stomachs, just as we might take Tums for an upset stomach! The mongoose family, including meercats, are actually immune to scorpion venom and can tolerate small doses of cobra venom. Here in North America, milksnakes and kingsnakes eat other snakes, including venomous ones.
Keep in mind that poisons and venoms are used for defense and one is not necessarily more dangerous than the other, they both can vary greatly in toxicity.
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