Mute as a Fish

But fish aren’t stupid

As the saying goes “Travel broadens the mind”: I agree, provided one is not only relaxing, basking in the sun, eating and drinking well and generally lazing around, but also takes an interest in learning something new and exploring the environment.

On a trip to a Japanese town by the name of Tsu in the prefecture known as Mie, I got to know a method that would allow me to go on an extended vacation without having to worry about who is going to feed my aquarium fish while I’m away. Dr Kohbara showed me some goldfish in his laboratory, which when hungry snap at a little bead that’s hanging in the water and is attached to a string that operates a switch of an electronic feeding machine. By pulling at the string, a knife tip of food is released from the feeder.

Sounds complicated? Not for the goldfish, for they learn after only two or three successful tuggings that this leads to food “falling from the sky”. Dr Kohbara and his students were able to show that even amongst goldfish you would find geniuses, who learn extremely quickly, and dumbwits, who don’t seem to get it. The researchers were also able to identify different characters and could distinguish between playful fish that were pulling the strings just for fun, and those who were more serious and would only operate the contraption when they were really hungry. And then there were the gluttons, who -once they had discovered how easy it was to obtain food- could not stop stuffing themselves.

I copied the set-up in my own lab and the student Keno Ferter (now Dr Ferter) found that Perches were as smart as Dr Kohbara’s goldfish. Dr Kohbara’s set-up made me think of some modifications to study some additional aspects of the fish’s intelligence. For example, what if there were extra strings that the fish could tug at, but that gave no food? Would the fish have a spatial memory and locate the one out of many that would provide the food? What if the beads at the end of the strings were of different coloration and even more interesting, would the fish be able to find the string that gives food also in the dark? Actually, they can.

A very tricky task, not yet tried, would be to teach a goldfish to first tug at a red string and then at a second differently coloured one and perhaps even a third, before food would rain down from above. Obviously, the visit to Dr Kohbara’s lab had been really worthwhile, which shows that Travel indeed broadens the mind. But it shows even more, because anybody who has ever dissected a fish brain (and this need not have been during the zoology lab practical at school or varsity, but could have happened on a plate with a trout-au-bleu in the restaurant or at home) would have been surprised at this organ’s minute size.

One may joke about a ‘bird brain’, but fish brains are a lot smaller still, and yet these water dwellers can master complex tasks (see above) – even in the dark. If they would see us humans stumble around at night in the dark to find the light switch, they might shake their heads and declare to their offspring “Oh, those human brains…”

Want to read about the fish muscles? Click here for : “Exercise – How does it strengthen the muscle”

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© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2016.
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