The Greening’s frog (Corythomantis greeningi). Photo by Carlos Jared, Butantan Institute

We are lucky in California. There are few venomous species that can kill a person. Sure there are rattlesnakes, but they are not aggressive and tend to avoid people. We have black widow and recluse spiders. But they rarely harm humans. Scorpions also live in California. But their venom is not considered dangerous.

But the rest of the world is not so lucky. In a moment of inattention, I nearly stepped on a Red-bellied Black Snake (Pseudechis porphyriacus) while hiking in Queensland, Australia. I remember thinking, “everything here seems to bite, envenomate, or sting.”

Science by Accident

Science sometimes happens by accident. And sometimes the accident is painful. Brazilian scientist Carlos Jared, a researcher at Instituto Butantan in Sao Paolo, can attest to this. Making the news last week was his discovery of the first known venomous frog.

He was collecting frogs in a forest reserve in southeastern Brazil when one of them head-butted his hand. Suddenly he felt intense pain radiating up his arm. The pain lasted five hours!

Dr. Jared and his team discovered the world’s first known venomous frog, the Greening’s frog (Corythomantis greeningi).

While poisonous frogs are well known, this is the first venomous frog discovered by science. The difference is important. Poisonous frogs secret toxins in their skin that cause illness or death if eaten. Venomous frogs inject their poison directly into the bodies of would-be predators. Jared and several co-authors documented their discovery in this scientific paper.

Here is a picture from the abstract that shows discrete spines on the frog’s head. These spines inject the venom.

Chart from abstract, “Venomous Frogs Use Heads as Weapons”

In truth, Dr. Jared was lucky. His team discovered a second venomous frog called Bruno’s casque-headed frog (Aparasphenodon brunoi). Its venom is 25 times more powerful than the fearsome fer-de-lance pit viper. Dr. Jared and his team determined that a single gram of the frog venom could kill more than 80 humans!

I should mention that the frogs’ spines are tiny. So they don’t inject large amounts of poison. This is why Dr. Jared remains happily alive.