Corythomantis greeningi and Aparasphenodon brunois, the name may look very innocent, but they are frogs that have skin secretions more deadly than the venom of pit vipers.

A single gram of secretion by A. brunois is enough to kill more than 3,00,000 mice or 80 humans. The capabilities of the frog dawned upon a Brazilian scientist in a rather painful way when he accidently touched the frog.

Carlos Jared, who was a researcher with the Instituto Butantan in Sao Paolo, was collecting frogs for his research from the Goytacazes National Reserve in southeastern Brazil. In the process, a frog head butted him jabbing its spines into his skin on his hand.

The jabbing of spines caused excruciating pain that spread up the arm and lasted for five hours. In this pain, the thought struck Carlos that there was something unusual with the frog. Frogs are known to secrete poisonous exudates that are toxic but not of this intensity. The frog is known as Greening’s frog or in the scientific nomenclature as Corythomantis greeningi.

The venom of the said frog was two times as powerful as the venom of a deadly local snake called the Brazilian pit viper.

Jared was lucky as the team discovered that another frog, Bruno’s casque-headed frog and in the scientific nomenclature as Aparasphenodon brunoi, possessed venom in its spines that were 25 times as powerful as pit viper venom. However, the spines of Bruno’s casque-headed frog were small and, therefore, could not inject much poison.

Neither frog is a new species, but very little is known about them. The modus of delivery of venom of the two frogs is the same. When threatened, both release a sticky secretion and flex their head pushing the spines into the hand. The frogs have the ability to move their head in a way no other frog can imitate thus maximizing the impact of their defense mechanism.

The frog’s process of delivering the venom on human hand may not be as effective as fangs, but it could be deadly on the mouth lining of an attacking predator. Therefore, the frogs have no known predators.