The rough-skinned newt is in an arms race that has turned it into the most poisonous animal in North America!
Most people would guess some sort of snake or spider is the most poisonous animal in North America, but it is actually the rough-skinned newt, and there is a very specific reason why!
While humans have known about newts for thousands of years, it was not until the 1960’s that their poisonous aspects were given serious consideration after three hunters were found dead with a newt in their coffee pot.
The newt is native to the West Coast of the United States, where garter snakes are plentiful. Garter snakes are the natural predator of rough-skinned newts, and while their poison seems to kill just about everything else, there is for some reason a strange resistance among garter snakes.
The reason? Evolution. Think about it as a sort of animal evolutionary arms race. The newt’s eggs are threatened by predators so they inject massive amounts of TTX, or tetrodotoxin, which is the poison newts posses, into their larvae so any predator dies immediately after eating them.
However, garter snakes have commonly fed on newt eggs, so while the newts continue to inject more and more poison, the garter snake has developed more and more immunities against it!
In a way, the newt is pushing the snake to become more immune to TTX and the snake is pushing the newt to become more and more poisonous!