An Early Education: As Embryos, Frogs Sniff Out Predators

Frog tadpoles have a good nose for danger: Scientists know that they go from headlong swimming to total stillness when they smell a predator. Now, researchers have discovered that frogs get that odoriferous training very early on. When they're still embryos, they can learn to assess the threat level by sniffing for a predator's pheromones.