Snakes Defend Themselves with Shape-Shifting Eyes

Superman donned glasses to disguise himself and blend in with other people. One snake hides its identity using a similar trick: when threatened, it changes the shape of its pupils. This makes it resemble a much more dangerous animal. The mock viper (Psammodynastes pulverulentus) is mild-mannered, not superpowered. It's common across much of Asia, and—as you might have guessed from its name—looks a lot like a viper. Actual vipers are a widespread family of venomous snakes. Like true vipers, mock vipers have triangular heads. Other details are different, though, such as the mock viper's round pupils. True vipers' pupils are vertical slits. Mock vipers carry only a mild venom; they're harmless to humans, for example. So imitating a more dangerous snake might help mock vipers scare off potential predators. In the summer of 2012, researchers from Thailand's Sakaerat Environmental Research Station were doing fieldwork in a forest in northeastern Thailand ...