Poisonous animals are different from venomous creatures in that they are only harmful if touched or eaten. For these animals, poison is a defense mechanism, rather than a offense mechanism, and they use it to ensure they don’t become prey. Let us show you the most poisonous animals on earth:
Blister beetles are insects that gained their name from the toxin they secrete, which causes blistering of the skin. Because of this, the toxin–called cantharidin–is used to medically remove warts. That’s some serious stuff!
Due to their toxicity, blister beetles are brightly colored, which serves as a warning to potential predators. Yet, interestingly, animals that eat blister beetles can become poisonous themselves. When spur-winged geese eat blister beetles, their flesh becomes poisonous, and they are dangerous to eat. Ten milligrams of cantharidin can kill a human, and that’s no laughing matter.
Pufferfish are rather adorable little fish, but they are also quite poisonous. Yet, in Japan, pufferfish–called “fugu”–are considered a delicacy, despite the lethal amounts of poison in their bodies. Their liver, ovaries, and eyes contain deadly amounts of tetrodotoxin, which is 1200 times stronger than cyanide and has no known antidote. So, when a person ingests fugu poison, their muscles become paralyzed, and they are unable to move or breathe, eventually dying from asphyxiation. Obviously, this not a pleasant way to die.
How and why do people eat fugu if they contain such horrendous amounts of toxins? Well, since 1958, fugu chefs have required a license to prepare this deadly dish. To acquire this license, the chefs must endure a two or three year apprenticeship and, then, go through an license examination process. Roughly 35% of applicants pass. So, with that in mind, fugu is relatively safe to eat, IF prepared by a properly licensed chef.
The flamboyant cuttlefish is another deadly sea creature on our list — The flesh of this colorful cephalopod is highly toxic, and it is on par with the toxins of the notorious blue-ringed octopus (which we have not included on this list because it bites prey/predators to unleash its powerful venom).
Thankfully, unlike fugu, the flamboyant cuttlefish is not considered a delicacy, and fisheries avoid it. However, due to their vibrant hues (which are intended to warn potential predators of their poisonous nature), aquariums around the world prize them.
Believe it or not, toxic birds are a thing. These birds retain toxins in their skin and feathers, which possibly protect them from external parasites and/or predators.
In New Guinea, toxic birds are quite common. The pitohui, the ifrita, and the rufous or little shrikethrush are all native to New Guinea, but they are all unrelated. Even so, these toxic bird species all share the same poison: batrachotoxin. They do not produce this poison on their own, but instead, they acquire it from the insects they feed upon. Melyrid beetles are their primary source of batrachotoxin, so if they do not consume these beetles, they will lose their toxicity.
Poison Dart Frogs
Poison dart frogs are tiny, colorful amphibians native to Central and South America, and they have most adorable beady little eyes. But don’t let their cuteness fool you: Secreting lipophilic alkaloid toxins such as allopumiliotoxin 267A, batrachotoxin, epibatidine, histrionicotoxin, and pumiliotoxin 251D through their skin, they are hopping death traps and probably the most poisonous animals on Earth.
Interestingly, like toxic birds, poison dart frogs do not create poison on their own. They are believed to acquire the chemicals necessary to create their poison by eating various alkaloid-rich arthropods, such as ants, centipedes, and mites. In captivity, when reared on diets without alkaloids, they are far less toxic.
Golden poison frog. Photo by Wilfried Berns.
Even more interesting (and frightening), the most poisonous of all poison dart frogs–the golden poison frog–has enough toxin to kill 10 to 20 men or 10,000 mice! This particular poison dart frog species secretes batrachotoxin, which is the same toxin found in the poisonous birds of New Guinea.