7 Tiny But Deadly Creatures

They say you shouldn’t sweat the small stuff, but you might reconsider that notion after looking at this list.

It just so happens that many of the deadliest creatures on Earth are also some of the tiniest (like the deathstalker scorpion shown to the right.)

In fact, it’s the diminutive size of these animals that makes them so terrifying: you might never see them coming.

Poison dart frogs

Bright colors in nature are often a sign of danger, and these flamboyant little frogs are no exception. The potent toxin secreted from their skin has been used by indigenous peoples in Central and South America to poison the tips of blowdarts.

poison dart frog

The most deadly species, the golden poison frog, carries enough toxin on average to kill 10 to 20 men. That’s impressive for a creature that only grows to about 1.5 inches in size.

Tsetse head fly

Tsetse fly

Houseflies aren’t the most charismatic of insects, but be thankful they aren’t tsetse flies. Though roughly similar to a housefly in appearance (and shown in close-up here, just to make you squirm), tsetse flies come equipped with a large proboscis, which they use to feed on the blood of large vertebrates. (Yes, that includes humans.)

That appetite for blood makes them a vector — meaning they transmit disease, in this case trypanosomiasis, or sleeping sickness. It’s estimated that as many as 300,000 people are infected with this debilitating disease, which results in swelling of the brain.

Blue-ringed octopus

Though extremely small (adults only grow to about 5 centimeters in size), the blue-ringed octopus is widely considered to be one of the world’s most venomous creatures. They’re docile by nature, but they will bite if agitated or accidentally stepped on at the beach. No antivenom currently exists for their bite.

blue ringed octopus


flea up close

Few creatures are as vile as the flea. These tiny, wingless, blood-sucking parasites are considered unsanitary for a reason: they spread disease. In fact, fleas were the vectors for one of the deadliest pandemics in history, the Black Death, also known as the bubonic plague.

Though the plague is uncommon today, it does still exist. Between 1,000 and 2,000 cases are reported each year worldwide.

Indian red scorpion

Widely considered to be the most lethal scorpion in the world, the Indian red scorpion is big, bad news in a small package. The creature only grows to about 50-90 millimeters in size, but that just makes it more difficult to detect. If you’re traveling in their home range of India, Pakistan, Nepal or Sri Lanka, make sure to shake out your boots before putting them on.



It may be difficult to believe, but the tiny mosquito is likely responsible for more human deaths cumulatively than any other creature. The list of deadly diseases that the mosquito carries and shares is long and terrifying. It includes malaria, yellow fever, dengue fever, encephalitis and West Nile virus, to name just a few.


Irukandji jellyfish

It’s the smallest jellyfish in the world. It’s also one of the most feared, capable of delivering a sting 100 times as potent as that of a cobra and 1,000 times as strong as a tarantula.

Though it is most commonly found in the waters off Australia, it has been found in locations around the world, including Florida. Its size is roughly no larger than a cubic centimeter, which means that jellyfish netting often provided at beaches in Australia offer little protection, if at all.

Irukandji jellyfish

Those stung by these teeny medusae suffer from what has been called irukandji syndrome, the symptoms of which include severe pains throughout the body, nausea, sweating, an increase in heart rate and blood pressure, and a constant feeling of impending doom. Yikes!