In the history of the animal kingdom, before goldfish started driving, there have been a handful of bold pioneers who set out to explore completely unfamiliar terrain. The very first was Pneumodesmus, a myriapod that left the sea for land 428 million years ago – before any other creature had dared do so.
Then came Rhyniognatha, which was possibly the first insect to detach its feet from the ground and glide in the air 400 million years ago. An honorable mention also goes to Homo sapiens, which exited the Earth’s atmosphere and walked on the Moon nearly 53 years ago. And now we can add to that list Carassius auratus, following a recent experiment in the Negev that saw one small step for goldfish, one giant step for all fish-kind.
In an innovative study, six goldfish were trained to navigate within an entirely foreign environment. The researchers, Prof. Ohad Ben-Shachar of Ben-Gurion University of the Negev’s department of computer science, who also heads the Be’er Sheva university’s interfaculty brain sciences school, and Prof. Ronen Segev from the BGU department of life sciences and department of biomedical engineering, designed a motorized fish tank on wheels.
The “vehicle” is fitted with a camera that monitors the fish’s location inside it: when the fish is next to one of the sides with its head in that direction, the FOV (Fish-Operated Vehicle) turns in that direction. In 10 days, by the classic conditioning process, the fish learned to “drive” the vehicle and steer it to a colorful plastic target that, when touched, brought them their favorite food.
The researchers say that following the learning process, the fishes’ driving changed from random to deliberate. They placed the FOV at different spots in the lab, and the fish were able to find the plastic target wherever it was placed.
“Up to now, a fish had to use its muscles to get to a certain place,” Ben-Shahar says. “But in the new experimental environment, it did this without swimming, completely opposite to its natural instincts. It only has to be at a certain point in the vehicle to take it in the desired direction.”
Thus, the fish learned quickly to navigate in an environment that is totally alien for them, and also to perform unfamiliar motor activity.
“It’s like learning to ride a bike,” Segev says. “You acquire a whole set of motor capabilities that you didn’t possess before. It appears that a fish is also able to acquire new motor capabilities.”
Well I'm bowl on wheels
The experiment and development of the vehicle were carried out with the aid of doctoral candidate Shachar Givon of the life sciences department and master’s candidate Matan Samina of BGU’s biomedical engineering department. The findings will be published next month in the journal Behavioural Brain Research.
Aside from expanding our knowledge about the capabilities of fish, the researchers also sought to explore how universal the navigational ability of animals is.
Navigation is a vital skill, which is important for finding food, shelter and a mate. Considering its basic role in the animal kingdom, the researchers wanted to see whether animals’ navigation mechanisms were specific to a species or ecosystem or brain structure, or whether they have general and universal qualities.
To test this, they used the innovative method of taking an animal out of its typical habitat and putting it in a completely foreign one. “The theory was that if we find a common denominator between what happens in the original habitat and what happens in the foreign one, it could be an indication of a universal ability,” Ben-Shahar explains.
In order to navigate, every creature must have a grasp of the space in which it is performing this task. The question then arises of whether this ability is dependent upon a specific environment. The findings from the experiment appear to indicate that this is not necessarily the case. “The fish adapted very quickly to its new task in the land environment, and seemed to solve it as if it were in its original marine environment – even though its brain structure is very different than that of land animals,” the researchers reported.
They also noted some major differences between the marine and land environments in terms of conceptualization. “The optics behave very differently in each of these places,” Samina says.
Givon adds: “Scuba divers are well aware that there are situations in which a sharp change in orientation occurs. In the experiment, the passage of light from the air through the plastic sides of the tanks and the water inside the aquarium create a situation in which the fish sees things completely differently from what it’s used to.”
But it didn’t take the fish long to learn how to control their new environment.
“Fish are no more primitive than we are,” Segev says, “but they developed in a very different evolutionary process from us over 450 million years. One of the things we’re trying to understand is: Despite our very different brains, what do we have in common with this creature? For example, in terms of vision.”
Segev adds that the preliminary findings from the latest experiment indicate that fish also have the ability to make a significant transformation in their abilities. “I can’t answer the question of what a fish sees when it comes out of the water, but that’s very interesting from a philosophical perspective,” he says. “In a way, we created an alien here: We took a fish from one environment and transferred it to a totally different environment.”