Scientists
are building fake animals to help them study real ones. But can a robotic
squirrel fool a real snake? WSJ's John Letzing reports.
The
snake in the grass didn't seem to believe in Rulon Clark's squirrel, which
could complicate matters for the professor.
Dr.
Clark had carried his prized ground squirrel into the hills near San Jose, Calif.,
last year to study the way squirrels' behavior affects predators. He placed it
by a grass patch he knew concealed a rattlesnake.
The
snake, perhaps not surprisingly, sprang and sank its fangs into the rodent.
Less predictable, for the rattler, was what happened next: The squirrel glided
backward, its face frozen in a placid expression.
The
snake flicked its tongue—a defensive signal—as if there were something odd
about this squirrel.
There
was: It was a robot.
"It's
likely that the snake realized as soon as it bit the fake squirrel that it bit
something that wasn't a live animal," says Dr. Clark, an assistant biology
professor at San Diego State University.
Trying
to dupe real animals with fake ones is an increasingly popular methodology
among biologists. The aim, they say, is to conduct focused, repeatable studies
on how animals respond to other creatures. Spurring the trend are ever-cheaper
motors, sensors and computer chips.
In
recent experiments, scientists have tried to infiltrate the animal kingdom with
robotic rodents, birds, frogs and fish, among other creatures. "It's
producing breakthroughs in animal behavior that would not probably have been
possible without these robotic models," says Sanjay Joshi, a mechanical
engineering researcher at the University of California, Davis, who has designed
versions of the squirrel over several years with his students.
Today's
robot animals build on earlier studies, such as the one that
persuaded cockroaches to come out of the dark. In an experiment that began in
2002, scientists in Belgium, France and Switzerland deployed cockroach robots
to mingle with real roaches.
Aiming
to influence roach behavior, they found that robot roaches coated with
pheromones could lead living bugs to hang out under brighter light if the fakes
ventured out first. The real roach's sentiment was probably something like
"Oh yeah, it's a friend of mine," says Simon Garnier, an assistant professor
at the New Jersey Institute of Technology who participated in the study.
Some
animals prove too eager to believe. UC Davis biologist Gail Patricelli this
year hid in a rural Wyoming hunting blind to study the mating habits of the
sage grouse using a robotic bird named Snooki, which she had built to make
natural-looking neck movements by using material from Spanx undergarments.
Robotic
Snooki was so persuasive that "a male jumped on her a few times this
season before she could escape," Dr. Patricelli says. Male suitors were
"not particularly choosy," she says, forcing her to jump out and shoo
them away, generally ruining the day's work.
Some
robots must merely blend in. Carrie Wall, while a University of South Florida
doctoral candidate, joined a study in the Gulf of Mexico using a torpedo-shaped
machine that mimicked a fish's buoyancy technique so it could stealthily
eavesdrop on real fish.
It
picked up an unexpected sound at night, which she says the researchers
hypothesized was herring passing gas to alter buoyancy. They published the
flatulence findings from the faux fish this year.
But
animal robots can have trouble staying in character. Barrett Klein, an
assistant professor of animal behavior at the University of Wisconsin-La
Crosse, joined a team seven years ago that is now studying the mating habits of
the túngara frog in Panamanian rain forests. His colleagues had a crude fake
frog with a manually-inflated condom to replicate the male's expanding vocal
sac—a mating signal.
Dr.
Klein and his team have since crafted increasingly realistic frogs made of
urethane with catheter-balloon sacs that inflate automatically. They find female
frogs near the Panama Canal and later, in a lab, present them with two
mechanical males that inflate their vocal sacs while mating calls play on
speakers.
The
female will usually choose a mechanical mate—if he stays in character. Several
times, a robot frog's vocal sac burst as he wooed. In one instance the live
female "just kind of stopped, turned and wandered away," Dr. Klein
says. "I can only imagine what she was thinking."
Even
harder to woo have been some politicians. Dr. Clark says his squirrel studies
are important for understanding animal behavior and thus worthy of the National
Science Foundation grant he received. "Our research is an important
contribution to our understanding of antagonistic co-evolution in general, and
the evolution of predator-prey communication in particular," he says.
Not
persuaded is Sen. Tom Coburn (R-Okla.), who in October put Dr. Clark's work in
his annual "Wastebook" of profligate federal spending alongside an
Iowa agricultural and motor sports museum and the overprinting of
"Simpsons" postage stamps, among other things.
"These
projects truly are representative of a broader problem, which is Washington's
inability to set priorities," says John Hart, a spokesman for Sen. Coburn.
"It's clearly unusual to spend taxpayer dollars on a robot squirrel."
Dr.
Clark says politicians shouldn't target funding like his while the U.S.
struggles to remain competitive in training scientists and engineers. Less than
5% of his $390,000 in grant funding went to robots, he says.
The
occasional serpent skeptic aside, Dr. Clark's pseudo-squirrels have been
successful enough that he plans to use a kangaroo-rat robot next year to study
how the critter's thumping foot affects predators.
The
robosquirrel evolved from less-polished strains. Aaron Rundus, as a UC Davis
graduate student, watched a primitive version face a snake several years back.
Everything went well until the squirrel's tail flew off. As the snake had now
seen the robot unmasked, the experiment halted, he says, because "you can't
erase that memory."
The
current model is made of hard foam and a pelt, and stored in a live rodent's
bedding for authentic odor. Dr. Clark seeks snakes in the brush and slides the
motorized squirrel toward them on a track. The squirrel waves an automated tail
heated by coils—to test the theory that real-life versions repel snake strikes
by heating up their tails and waving them.
He
says he hasn't completed his field experiments yet. It may become clear that
the snakes haven't sufficiently bought his impostor squirrel all along, he
says. "If that happens, we're back to square one."
Video
of Comeback of Japanese Giant Salamander
http://video.nationalgeographic.com/video/news/animals-news/giant-salamander-wcvin/
Posts
