Forget about Ginger, or "IT," or whatever its name is. The invention the world really needs is a gizmo that can swim like a fish while grabbing stuff from the water with several arms, and still be able to smell like a lobster.
That may sound a bit strange, but in fact scientists are increasingly turning to animals like the octopus and the lobster for help in designing the robots of the future. The reason is simple. Nature did it first and did it best, so we ought to be able to learn a lot by looking at biological systems that do some things a lot better than we can.
Much of the research is supported by the military, particularly the Office of Naval Research and the Defense Advanced Research Projects Agency, because it would be a lot safer to send a robot into a cave instead of a soldier. To figure out how to build such a robot, scientists are studying all sorts of critters to see how they function in what would seem to us a very hostile environment.
Take the Caribbean spiny lobster, for instance. Panulirus argus can sniff out odors underwater (when was the last time you tried that?) and distinguish between prey and food.
That's a really nifty trick, and if scientists could figure out exactly how the lobster does that, they would be a bit closer to building robots that can follow scents under water.
So scientists at the University of California at Berkeley and Stanford University are trying to figure out exactly how a lobster smells. It turns out to be an extremely complex system. The lobster uses odor-sensitive hairs in its antennae to pick up the scent of a tasty morsel, like a rotten fish.
"When you look at the animal kingdom, you see lots of creatures that capture odor from water or air using antennae that are feathery or hairy," says Mimi A.R. Koehl, professor of integrative biology at Berkeley and lead author of a report on the research in the Nov. 30 issue of the journal Science.
"We want to know how these feathery structures interact with water or air … and which aspects of their design affect how they perform at catching odors."
The researchers used high-resolution video cameras to capture images of the lobsters sniffing around in an aquarium. That gave them a few clues, but it's pretty hard to train a lobster, so to test out their findings they created a robotic lobster that could mimic the real thing.
Stroke, Stroke, Smell
The images revealed that when the lobster is trying to smell something it initiates a series of movements with its antennae. First, there's a very rapid down stroke, lasting only about 100 milliseconds, followed by a slower upstroke of about 300 milliseconds, and then a 400-millisecond pause.
Each of those functions appears to play a key role in the lobster's olfactory system. The down stroke is just the right speed to cause water to swirl around tiny odor-sensitive hairs near the tip of the antennae, capturing any chemicals that might indicate the source of an odor. The upstroke apparently is slower so the lobster can try to figure out exactly what the trapped chemical — or the odor — is. And the pause allows the animal to flush out its system as it prepares to sniff again.