The Brazilian rainforest has offered up yet another hidden treasure—sort of. Two new frog species were recently discovered which, in itself, is a newsworthy event, but these little amphibians are getting a lot of attention because they also happen to be the first two venomous frogs ever discovered. Unlike their poison-secreting cousins, these little guys use tiny spines on their heads to inject lethal venom directly into the bloodstream of any foe.

venomous frogs, Brazil, Bruno’s casque-headed frog, Aparasphenodon brunoi, Greening’s frog, Corythomantis greening, Carlos Jared, Butantan Institute, Edmund Brodie, Utah State University

You might think that these frogs would have just enough venom to kill their intended prey or ward off a would-be predator. Not so. One of the species—Bruno’s casque-headed frog aka Aparasphenodon brunoi—could kill 80 people or 300,000 mice with just one gram of its venom. That makes the little frog 25 times more poisonous by weight than a Brazilian pit viper, a snake that grows up to five feet in length.

Related: Glowing frog skeletons shed light on unexplained deformations

The other venomous frog species—Greening’s frog or Corythomantis greening—has less potent venom than the first and is only twice as poisonous as the pit viper. Amazingly, the two species live in the same area, the Caatinga forest in the state of Rio Grande del Norte.

Carlos Jared of the Butantan Institute in São Paulo, Brazil, is one of the field researchers who encountered the dangerous amphibians, and he learned the hard way how the frogs can inject their poison. One of the frogs he was collecting managed to pierce Jared’s hand, and luckily, it was one of the less dangerous Greening’s frogs. Jared’s colleague Edmund Brodie of Utah State University recalls the incident. “Intense, immediate pain radiated up his arm and lasted five hours,” said Brodie “He was many hours from any medical services, so just toughed it out.”

Brodie, Jared, and their team are now on the hunt for other venomous amphibians, and we can be pretty certain they will proceed with much caution.

Via New Scientist

Images via Carlos Jared/Butantan Institute