Venomous Frogs Deliver Poison Through Toxic Head Spines

Posted on August 7, 2015

Corythomantis greeningi

Scientist Carlos Jared of Instituto Butantan in Sao Paulo was poisoned by a venomous frog in Brazil. The frog, Corythomantis greeningi, carries venom in spines located on its head. The frog is also known as Greening's frog. Jared's hand was injured by one of the frog's spines. This led to intense radiating pain that lasted for five hours.

The scientists determined that two frog species - C. greeningi and Aparasphenodon brunoi - have toxic spines. Scientists were not aware of these spines before. Jared would have been much worse of if he had been poisoned by the second species. The researchers calculated that a single gram of the toxic secretion from A. brunoi would be enough to kill more than 300,000 mice or about 80 humans. The image below shows the skull of C. greeningi and its many spines.

Spines of Corythomantis greeningi


The frogs could potentially use their heads as weapons to deliver the toxin. A predator could die if it tried to make a meal of one of these frogs. Jared says, "This action should be even more effective on the mouth lining of an attacking predator."

Edmund Brodie, Jr., a co-author of the study from Utah State University, says in a statement, "Discovering a truly venomous frog is nothing any of us expected, and finding frogs with skin secretions more venomous than those of the deadly pit vipers of the genus Bothrops was astounding."

A research paper on the findings, "Venomous Frogs Use Heads as Weapons," can be found here in the journal, Current Biology.

Photos: Carlos Jared/Butantan Institute