Mechanical animals aid behavior research

They focus on whether squirrels react more strongly to Rocky's noises or movements or a combination that researchers call multi-modal signals.

Although animal behavior has been studied for years, much remains unknown about instinctive responses.

A particular sound may be the courting equivalent of, "Come over here, you sexy beast.'' But a tiny change can alter the message entirely, making it something akin to, "You're about to be torn to shreds if you don't get out of my territory.''

"Whether it's a bunch of squirrels in a field or humans in a mall, there are general principles of behavior that seem to hold up across species lines,'' said Greg Demas, director of Indiana University's Center for the Integrative Study of Animal Behavior and an associate professor of biology.

Robot critters also can help researchers discover how far a species can be pushed beyond its survival instincts.

Researchers at the Free University of Brussels, for instance, found that fake roaches doused in familiar pheromones became so accepted among their cockroach compatriots that the real bugs succumbed to the interlopers' peer pressure to move out of dark areas into the light.

In other experiments, a robotic lizard developed by Indiana University researcher Emilia Martins uses energetic push-ups to trigger similar displays of courtship, power and machismo among real lizards.

Depending on the fake lizard's prompting, the real critters react as if they're being taunted, threatened or titillated — all of which gives researchers a chance to study the tiniest movements of their legs, eye flaps and other quirks.

"There's been the old, classic trade-off for years between the ecological relevance you get (researching) in the field, versus those studies in the lab where you can control the environment while knowing they're not going to react as much,'' Demas said. "Having these models out in the field is taking us to the next steps of the research.''

Researchers say the applicability of fake animals in research can depend on the intelligence, size, eyesight and sense of smell in the real species.

"The bigger the animal is and the more complicated it is, the harder it is to have a proper robot that mimics the signals and has the right visual cues,'' said Cornell ornithology professor Jack Bradbury.

Bradbury's research has ranged from vocal mimicry in wild parrots to the sexual choices of hermaphroditic sea slugs. He hasn't used robots but does use sound cues — emanating from speakers hidden in bushes — to manipulate animals in the wild by "talking'' with them or playing noises they recognize.

"Wild parrots are pretty smart, but I've gone on for hours interacting with them that way,'' he said. "They come up to the bush and look at it and don't see the birds, but they keep communicating with the belief there's another parrot in there somewhere.''

He said mechanical animals aren't used "just to be clever.''

"The real issue from a scientist's point of view is, 'Can I come up with a robot that will help me answer a question that I couldn't answer otherwise?'''

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