Why, You Dirty Rat!
Recently eaten: meatball sub
Recent annoyance: decaf tea (why bother?)
After various, somewhat unsuccessful bouts with rodents in DC, I was startled to find even more evidence of their plot against people.
World's most elusive rat dead after 18-week chase
"It seemed like a good idea. Let a lone rat loose on a rodent-free island and then figure out how to kill it. That way, when other islands are invaded by rats, you'll know what to do.
Scientists figured they'd trap this foot-long varmint in no time.
Eighteen weeks later, they finally trapped it with some fresh penguin bait. On another island.
A real rat race
Rodents are a problem just about everywhere. In New Zealand, at least 11 islands have been invaded by Norway rats since 1980, in each case after rats from earlier invasions had been eradicated. The invaders disrupt local ecosystems.
In the new study, announced today, a Norway rat was originally lured into a trap with chocolate. Its DNA was recorded, and the rat was outfitted with a radio collar and set free on the tiny island of Motuhoropapa off the coast of New Zealand.
With no rats to compete with, the test subject traversed the entire island for about four weeks before settling on a home range, data from the radio collar showed.
For the next four weeks, conventional rat-trapping techniques were employed -- snap traps, live traps and waxed devices -- without success.
After 10 weeks, the radio signal was lost.
Island hopping
Then the researchers found rat feces on the island of Otata, 1,300 feet (400 meters) away across the open ocean. The DNA was a match, confirming a suspicion scientists had, that rats were good swimmers.
The elusive creature had made the longest confirmed open-water crossing of any rodent in history.
Different methods were used on Otata: buried traps, peanut butter, poison and even trained dogs. Not until more than four months after its release was the rat finally killed, in a trap baited with fresh penguin.
The scientists, led by James Russell at the University of Auckland, sagely conclude that conventional methods didn't work well. They also have an idea why: Being alone, the rat didn't behave as it would have in a rat-infested city; and with no competition for food, the bait was less attractive than it otherwise would have been.
The results are detailed in the Oct. 20 issue of the journal Nature.
"Our results may help in the design of conservation strategies to keep islands free of invasive rodents," the researchers write."
Plot: A rat is let loose on the rat-free ice floe the penguins are nesting on. Havoc ensues as eggs begin to disappear right out from under their feet. Starring Jessica Alba as Dr. Madison Jones, marine biologist and former pest control officer, and Scott Wolf as Finn O'Shea, the rogue fur trapper and sometime penguin egg poacher. Is Finn stealing the eggs to sell on the black market? Can he be trusted? And what happened to that rat we let loose 18 weeks ago?
Eek! Robo-rats make their own rules
"In a test that might've sent some folks shrieking from the room, robots programmed with no more sense than a blind, deaf baby rat developed new behaviors on their own.
Welcome to biorobotics, an emerging field in which automated machines are used to study living creatures -- and vice versa.
Trapped in a corner
Psychology professor Jeffrey Schank and mechanical and aeronautical engineering professor Sanjay Joshi, both of the University of California, Davis, designed an experiment to record the behavior of young rats and robots that were confined to the same basic sets of rules in a rectangular arena.
Rat pups that were just seven to 10 days old and blind and deaf felt their way along a wall until their nose hit a corner, where they would stay put. The behavior was considered a rule.
Joshi then built foot-long robots, with tapered snouts to mimic the shape of a rat pup. The robots were ringed with sensors so they could feel when they bumped into a wall or corner. They were programmed to stay in contact with objects they touch, the same as the basic rat pup rule. They has the same basic motor skills.
When the robotic rats were placed in a similar rectangular arena, they showed different behavior than their furry counterparts. Instead of huddling in a corner, the robots circled the arena, scuttled along the walls and repeatedly bumped into one corner.
Emergent behavior
The behavior exhibited by the robots was not included in the written computer code, but instead emerged as a combination of the written instructions and interactions with the environment at each instant. Joshi says this is evidence of what scientists call emergent behavior, or new and unexpected behavior that grows from a simple set of rules.
The robots preferred one wall over the others. Turns out the rat pups did, too.
"We are still looking into the reasons for why the baby rats prefer one wall," Joshi told LiveScience. "It could be the result of how they get into the corner in the first place, mixed with what their brain tells them to do once they hit a wall. We can use the robots to test out our different hypotheses."
More to learn
The team is also looking at the behavior that emerges when groups of robotic rats interact using different kinds of rules. Results from this type of experiment may help biologists determine what rats may be doing in groups.
"The robots can help us create controlled experiments that would not be possible using live animals," Joshi said. "In the future, we hope to create more and more sophisticated and realistic robotic models of living creatures to help understand the creatures themselves."
And understanding the biology of these simple systems might later inform the design of more sophisticated robots.
"Understanding how animals achieve complex behavior using simple actions as building blocks could help us design robots that can do the same thing," Joshi said."
A blind, deaf baby rat learns to communicate with others with the help of her dedicated teacher.
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