Creatures consuming species that contain deadly toxins have evolved a suite of clever strategies to stay alive.

The 10 snakes faced a tough predicament.

Collected from the Colombian Amazon, they had been without food for several days in captivity and then were presented with extremely unappetising prey: three-striped poison dart frogs, Ameerega trivittata. The skin of those frogs contains deadly toxins – such as histrionicotoxins, pumiliotoxins and decahydroquinolines – that interfere with essential cell proteins.

Six of the royal ground snakes (Erythrolamprus reginae) preferred to go hungry. The other four intrepidly slithered in for the kill. But before swallowing their meals, they dragged the frogs across the ground – akin to the way some birds rub toxins off their prey, noted biologist Valeria Ramírez Castañeda of the University of California, Berkeley, and her colleagues, who conducted the experiment.

Three of the four snakes survived the meal – suggesting that their bodies were capable of handling the toxins that remained.

Living beings have been wielding deadly molecules to kill each other for hundreds of millions of years. First came microbes that used the chemicals to weed out competitors or attack host cells they were invading; then animals, to kill prey or ward off predators, and plants, to defend against herbivores. In response, many animals have evolved ways to survive these toxins. They sometimes even store them to use against opponents.

Scientists are beginning to unravel these creative antitoxin defences and hope as a result to identify better treatments for poisonings in people. More fundamentally, they're learning about a force that has quietly helped to shape biological communities, says evolutionary biologist Rebecca Tarvin of University of California, Berkeley, who helped supervise the snake experiment and wrote about such strategies in the 2023 Annual Review of Ecology, Evolution, and Systematics.

"Just milligrammes of a single compound, and that can change all of the interactions in an ecosystem," Tarvin says.

Species become toxic in a variety of ways. Some of them make the toxins themselves: Bufonid toads, for instance, produce molecules called cardiac glycosides that stop a protein called the sodium-potassium pump from shunting ions in and out of cells. Such shunting is critical to maintaining cell volume, contracting muscles and transmitting nerve impulses.

Other animals house toxin-producing bacteria in their bodies – that's the case for pufferfish, whose tetrodotoxin-containing flesh can prove lethal to consume.

And many others get their toxins through food – examples are poison frogs, which devour toxin-containing insects and mites; those frogs include the species that was fed to the ground snakes.

As some animals evolved to become toxic, they also rewired their bodies to avoid poisoning themselves. The same thing happened to creatures they eat, or that eat them. The best studied of these adaptations involves changes to the proteins that are normally disabled by the toxins, so that they're now........

© BBC