An old joke goes like this: Two fish are in a tank and one says, "Do you know how to drive this thing?"
Israeli scientists appear to have found the answer.
A team from Ben-Gurion University has successfully taught goldfish to maneuver a robotic car on land, via a top-down camera that monitors their movements around a small fish tank.
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The camera in the "fish-operated vehicle" uses motion sensing technology to send a signal to one of its four wheels whenever a fish swims close to a side of the fish tank. Over time the fish learned that their movements would correspond to the movements of the vehicle.
The fish were successfully trained to reach a pink target at the opposite end of a room in return for a fish food reward - something they could do repeatedly and even with obstacles in their way.
The researchers say their study, published this month in the peer-reviewed Behavioral Brain Research journal, shows that the navigational abilities of fish stay intact in a land-based environment.
The process is called domain transfer methodology, when one species is placed in another's environment and carries out an otherwise familiar task - in this case navigation.
And for one of its authors, this shows that humans and fish may not be quite as different as some think.
"If you look at the phylogenetic tree of evolution, the branch that we sit on and the branch that fish sit on just diverged away 450 million years ago," said Ronen Segev, a professor at Ben-Gurion University, who has long studied the behavior of fish.
"It's not that fish are primitive, they just developed in a very different world from us. They need to solve sophisticated [problems] to exist in their environment."
At first the fish struggled to figure out how the navigation system works. But after a while they "were able to operate the vehicle, explore the new environment, and reach the target regardless of the starting point, all while avoiding dead-ends and correcting location inaccuracies, " the study said.
Segev said that future studies could test whether fish could navigate in more trying circumstances, such as finding a target they can't see at first.
Six goldfish took part in the study, the biggest measuring just 7 inches and weighing no more than 4.2 oz. They each received 10 driving lessons.
The fish were named after characters from Jane Austen's "Pride and Prejudice" - Mr. Darcy and Mr. Bingley were two outstanding stars, researcher Sachar Givon has said.
The study may also help to dispel the popular myth, many times debunked, that a goldfish's memory lasts only a few seconds.