Secreted from the glands of poison dart frogs in South America, batrachotoxin is fatal at a dosage of just 0.1 milligrams. That’s equivalent to around two grains of table salt. After exposure, the toxin jams open the ion channels in its victim’s nervous system, forcing muscles to fire continuously. In around 10 minutes, the heart and lungs will seize.
Batrachotoxin just about the most potent toxin on the planet. But killing power aside, the most compelling thing about batrachotoxin is how it reveals large holes in our understanding of evolution.
In 1989, a graduate student from the University of Chicago named Jack Dumbacher was studying birds of paradise in Papua New Guinea. He was trying to catch them in nets but kept getting another bird, called a pitohui, instead.
“So I had two or three in a net and was pulling them out, and they scratched my hand,” he recalled over the phone. “I licked my cuts and instantly felt my tongue start to tingle and burn. After a moment it went numb and I thought Hey, maybe I shouldn’t have done that.”…