Science Interviews


Sun, 16th Jul 2006

Science Update Frog's Legs and Gunshots

Chelsea Wald and Bob Hirshon from AAAS, the science society.

Part of the show Sun Tans, Fission and Fusion


Kat - We're now going to go over to the US to hear from Chelsea and Bob with our Science Update. They're going to talk about frogs eggs that literally leg it when a hungry snake slithers by, and a robot called Red Owl who can pinpoint the source of gun shots on the battlefield.

Bob - This week for the Naked Scientists we'll learn about a technology that mimics human hearing and could help soldiers on the battlefield. But first, in nature eggs are sitting ducks, but Chelsea learned that some types of eggs may not be as helpless as they seem.

Chelsea - It's hard to imagine your breakfast egg running away from a predator but the eggs of the red eyed tree frog can do just that. Biologist Karen Walkentin of Boston University has found that these eggs hatch prematurely when an egg is in imminent danger from a snake.

Karen - And it's a very rapid behavioural response. The snake starts biting and within seconds to a couple of minutes the tadpoles will bale out. Up to 80% or so can escape from the snakes.

Chelsea - But premature tadpoles don't face good odds, so they need to be able to tell a real snake from a false alarm.

Karen - It's such a big decision for them and it's a question of death in one place versus death in another place.

Chelsea - Their secret? Walkentin's experiments show that the eggs use vibrations to distinguish between snakes, wasps, rain and wind and are accurate even when the vibrations are similar.

Bob - Thanks Chelsea. A robot called Red Owl may soon help soldiers locate the source of gun shots. It's based on sound processing technology originally designed to improve cochlea implants for deaf people. New field tests show that this new technology can accurately identify and log the locations of many shots in rapid sequence, like those on a battlefield. Engineer Socrates Deligeorges of Boston University says that it's modelled after the way humans and other mammals hear.

Socrates - Basically neuron by neuron, how the mechanical structures take sound pressure waves, how the brain converts those to electrical signals and how the brain uses those electrical signals.

Bob - Once Red Owl locates the source of the gun shot it turns to the shooter and zooms in with a camera. Although it could still be a while before Red Owl makes it to actual battlefields, Deligeorges says the sound processing technology has proved useful in many other situations. These include monitoring machinery and even taking a census of frogs.

Chelsea - Thanks Bob. Next time we'll learn about scientists developing replacement retinas that use chemicals to communicate with the brain. Until then, I'm Chelsea Wald.

Bob - And I'm Bob Hirshon for AAAS, the science society, Back to you Naked Scientists.


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