Transcript:

Scorpions Hiss!Esposito: They're called the hissing scorpions because they make a hiss, an audible hiss that humans can hear. Ambience: Hissing CockroachesThree new species of hissing scorpions have been discovered in South America. I'm Jim Metzner and this is the Pulse of the Planet. Esposito: And we're 100 percent certain that they're making that hiss in order to keep their predators away, to scare them; something like a rattlesnake.Lauren Esposito is the Curator of Arachnology at the California Academy of Sciences in San Francisco. Full disclosure the sounds we're hearing are just like the scorpions, but they're made by Madagascar Hissing Cockroaches.Esposito: And the way that hissing cockroaches make noise is by expelling air or pushing air out of a hole on the side of their body. Hissing scorpions make sound in a very different way, although it sounds quite similar to what a hissing cockroach sounds like.The way that they make sound is similar to a cricket, where they rub one part of their body against another, but it sounds much more soft and "shussy" - kind of like a hissing cockroach. And it's used for the same function. Hissing cockroaches also expel air to make a sound to warn predators away.I think it's quite shocking the first time you hear it, so scientists have written about it in scientific publications for a long, long time. And we've actually gone out into the field and sought out all of the species of hissing scorpion in the world. And they're found everywhere from the Caribbean to most of northern South America. And what we discovered was that there was three species that scientists had never previously recorded. Two of them are found in Brazil and one of them is found in Venezuela. And we were really excited to make this discovery, particularly because these scorpions are so charismatic with this loud hissing noise that they make, and often they're much larger than many of the other species of scorpions we find around those areas.I'm Jim Metzner and this is the Pulse of the Planet.