Most venomous frog

While poisonous frogs that secrete toxins through their skin have long been known about, the first venomous frogs were only documented in 2015. Two Brazilian hylid frogs – Greening's frog (Corythomantis greeningi) and Bruno's casque-headed frog (Aparasphenodon brunoi) - were both found to possess small bony spines on their heads which, via "headbutting", enable them to inject venom into would-be attackers. Of these, the most venomous was the latter, with an LD50 body weight toxicity of 0.16 to 0.24 mg/kg, equating to 1 g (0.04 oz) of Bruno's casque-headed frog venom being enough to kill 80 adult humans or 300,000 mice. The findings were published in the journal Current Biology on 6 August 2015.

The term LD50 represents the dose of venom that proves lethal to 50% of a test population.

<p>Greening's frogs have larger skin glands and soare capable of producing more toxic secretions, but their venom is less potent, though still equivalent to double the toxicity ofBrazilian pitviper snakes (genus <i>Bothrops</i>), such as the notorious fer-de-lance; Bruno's casque-headed frog venom, meanwhile, is <i>25 times</i> more toxic by weight than that of <i>Bothrops</i> snakes.</p>

The study was a collaboration between the Instituto Butantan, the Universidade de Sao Paulo (both Brazil) and Utah State University (USA), led by Dr Carlos Jared of the Instituto Butantan.