LOURDES GARCIA-NAVARRO, HOST:
And now let's talk frogs. The life of a frog usually starts in water. A female lays eggs. A male fertilizes them. They become tiny tadpoles. Tadpoles grow into frogs. But there's one frog species that takes a radically different approach to reproduction as scientists recently discovered. NPR's Nell Greenfieldboyce reports.
NELL GREENFIELDBOYCE, BYLINE: As a kid growing up in Southern California, Jim McGuire dreamed of a career studying reptiles and amphibians. He collected his first snake at age five. Not too many frogs lived nearby, but he managed to find them.
JIM MCGUIRE: There was a place near the railroad tracks, and there were Pacific tree frogs there. And I collected some of those, including their tadpoles, and brought them home. I don't even remember what happened to them to be honest, but whatever happened to them probably was not good.
GREENFIELDBOYCE: Now he's a researcher at the University of California, Berkeley, who does his frog collecting in the rainforests of Southeast Asia. Not too long ago, on an Indonesian island, he and some colleagues euthanized one frog to dissect it. When they cut it open, they got a shock.
MCGUIRE: Out came the tadpoles, and they were alive.
GREENFIELDBOYCE: He says the shimmery, quivering tadpoles looked creepy.
MCGUIRE: I mean, it was very reminiscent of the scene in "Alien" where the little monster, you know, explodes out of the stomach of the poor human who's been impregnated with that larval alien.
GREENFIELDBOYCE: The scientists described their find in the journal "PLOS ONE." McGuire says some other frogs do bizarre things to reproduce. A couple of extinct frogs would swallow fertilized eggs and use their stomach as a breeding chamber, then give birth out of their mouths. Other frogs have special pouches on their backs to carry eggs. But McGuire says this is the first frog known to give birth to live tadpoles.
MCGUIRE: This is, you know, another pretty crazy reproductive mode that's evolved within frogs. And so, you know, frog biologists are turned on by that sort of thing.
GREENFIELDBOYCE: It's the kind of discovery even a kid might think was cool. Nell Greenfieldboyce, NPR News.