It might seem like a fish needs a car like — well, like a fish needs a bicycle. But a new experiment suggests that fish actually make pretty good drivers.
In the experiment, several goldfish learned to drive what is essentially the opposite of a submarine — a tank of water on wheels — to destinations in a room. That these fish could maneuver on land suggests that fishes’ understanding of space and navigation is not limited to their natural environment — and perhaps has something in common with landlubber animals’ internal sense of direction, researchers report in the Feb. 15 Behavioural Brain Research.
Researchers at Ben-Gurion University of the Negev in Beer-Sheva, Israel taught six goldfish to steer a motorized water tank. The fishmobile was equipped with a camera that continually tracked a fish driver’s position and orientation inside the tank. Whenever the fish swam near one of the tank’s walls, facing outward, the vehicle trundled off in that direction.
This goldfish knows how to use its wheels. Successfully navigating in a tank on land suggests that the animals understand space and direction in a way that lets them explore even in unfamiliar habitats.
Fish were schooled on how to drive during about a dozen 30-minute sessions. The researchers trained each fish to drive from the center of a small room toward a pink board on one wall by giving the fish a treat whenever it reached the wall. During their first sessions, the fish averaged about 2.5 successful trips to the target. During their final sessions, fish averaged about 17.5 successful trips. By the end of driver’s ed, the animals also took faster, more direct routes to their goal.
Some of the fish — all named after Pride and Prejudice characters — were speedier learners than others. “Mr. Darcy was the best,” says study coauthor and neuroscientist Ronen Segev.
In further experiments, the goldfish were still able to reach the pink board when starting from random positions around the room, rather than the center. This finding confirmed that the fish had not merely memorized a choreography of movements to reach their reward, but were planning routes toward their prize each time. When the researchers tried to trick the goldfish by placing decoy boards of different colors on the other walls or moving the pink board to the other side of the room, the fish were not fooled, and navigated to the pink board.
“That was pretty conclusive that the fish actually navigate,” says study coauthor Ohad Ben-Shahar, a computer scientist and neuroscience researcher. Recently, the team let a goldfish take a joyride throughout an entire building, Ben-Shahar says, “and it actually started to explore. It went down one of the corridors and started to sneak away.”
Behavioral neuroscientist Kelly Lambert is “not completely surprised, but still intrigued” by the driving abilities of Mr. Darcy and his fish friends. In her own research at the University of Richmond in Virginia, Lambert has taught rats to drive toy cars. But teaching goldfish to navigate such alien terrain takes animal driving experiments to the next level, Lambert says. “I love the fish-out-of-water idea.”
When it comes to testing the bounds of animal navigation, “it’s important to diversify and expand our tasks and our species,” Lambert says. “I think we need an international race between the rats and the goldfish.”