Fish that enjoy a wellness treatment or react to antidepressants? In his book, behavioral biologist Jonathan Balcombe dispels prejudices about the cold, emotionless fish. But be careful, reading the book carries risks and side effects.
When Jane Goodall gave chimpanzees names during her field observations in Tanzania and observed behavior reminiscent of humans, the research community turned up its nose and spoke of humanization. Today we know: chimpanzees and humans share 98.6 percent of their genetic makeup. Our closest relatives can make tools, pass on traditions within their clan and are capable of empathy.
The cold, emotionless fish
However, when it comes to fish, even animal lovers wonder whether they are capable of forming social bonds or feeling anything like pleasure. And some even deny them the ability to feel pain. Jonathan Balcombe is certain that fish have a problem. Unlike great apes, they are not like us. They have neither hands nor feet and they have no facial expressions; they cannot even blink. Because they are so different from us, we find it difficult to feel empathy for them. But this changes after reading the book "What Fish Know" by the behavioral researcher Jonathan Balcombe.
Fish and Emotions: Depressed Zebrafish
Do fish have feelings and do they have some kind of intelligence? In his book, Balcombe uses scientific studies to show that there are numerous parallels between humans and fish. Fish have feelings. The brains of bony fish and mammals send out hormonal messages in almost identical ways. Balcombe describes an astonishing experiment that was carried out at the Max Planck Institute for Neurobiology at the University of California. Zebrafish were examined there and showed signs of depression. The fish were placed individually in a new aquarium. Normally, the fish get used to the new situation after a few minutes and explore their new surroundings. The genetically modified fish, however, had difficulty getting used to the new environment and reacted to being alone by sinking to the bottom of the aquarium and remaining there motionless.
The behavior only changed when two drugs were added to the water: Valium for anxiety and an antidepressant. Interestingly, visual contact with conspecifics also alleviated the depressive behavior. Jonathan Balcombe
Wellness treatment with the cleaner fish
But can someone who is suffering and showing signs of depression also feel something like joy and pleasure at the other end of the emotional spectrum? In another experiment, two models of cleaner fish were placed in an aquarium, one with movable fins and the other without. The fish approached in the hope of being cleaned. Since the model fish could not do this, of course, the fish quickly lost interest - at least in the model that did not move. But they kept returning to the other cleaner fish and allowed themselves to be stroked by the movable fin. These strokes reduced the cortisol level in the blood and thus the stress.
Underwater Love ❤️ As Balcome shows, love life under water is extremely diverse. It ranges from couples who stay together for life to harem-like constellations and fish that change their gender over the course of their lives. The repertoire for attracting future partners is also large, there are dances, love songs and one species even creates small works of art. The Japanese puffer fish creates geometric circles up to almost two meters wide, a kind of mandala or "land art" underwater. The male, which is only twelve centimeters long, swims on his side, fans himself with a pectoral fin and thus draws his shapes in the sand. In between, he looks at his work from a distance and sprinkles in pieces of mussel shell. His work is intended to impress a female and get her to lay her eggs in the center of the work of art. The furrows are not just decorative, they also have a function: they prevent the spawn from being immediately carried away by the current. Many species of fish give everything for love, but the Japanese puffer fish is also an artist and designer. |
Jonathan Balcombe, born in 1959 in Hornchurch in southern England, grew up in New Zealand and Canada, and has lived in the USA since 1987. He holds a doctorate in behavioral biology and is a sought-after expert on animal sentience and has written several books on the subject. He also heads the Animal Awareness Department at the Humane Society Institute for Science and Policy in Washington, DC.
When fish fingers invent tools
But what about intelligence in the fish kingdom? People consider those animals that use or make tools to be intelligent. According to Balcombe, intelligence also varies among different fish species. In general:
"Evolution produces as much intelligence as a species needs to survive in a particular environment."
The Atlantic cod, a fish that many people only know as fish fingers, has proven to be particularly resourceful. In an experiment, the fish learned to pull on a loop to trigger a feeding mechanism. So far, so good, but the fish developed a different strategy. In order to be able to distinguish the fish, the experimenters marked them with a colored plastic tag near the dorsal fin. Apparently by chance, the fish discovered that they could hook themselves into the loop with the plastic tag. They then practiced hooking the loop onto this plastic tag with numerous attempts. As soon as they had succeeded, they triggered the feeding mechanism with a strong pull. The advantage of this strategy? Their mouths were free, they were closer to the food source and thus increased their chance of getting a tasty morsel.
The Atlantic cod has turned the experimental setup – we would say creatively – to its advantage.
Fishes with a sense of hierarchy
When fish move in schools, it is impossible for humans to recognize individual fish. Balcombe shows that fish can do this. They also recognize their neighbors in the reef. If these come to their territory, they are not attacked, but foreign fish are immediately attacked. But some species of fish - like horses, for example - also appear to have a strong sense of hierarchy.
Mouthbrooders, which belong to the East African cichlid family, have developed a strong sense of their position within the community. They can deduce that if fish A is higher than fish B and fish B is higher than fish C, then fish A must be higher in rank than fish C. Too complicated? Apparently not for mouthbrooders.
A new look at fish
Anyone who has read Jonathan Balcombe's book will see fish with different eyes. As social, sentient beings that are capable of experiencing pain and pleasure. Of course, we can never be sure what another living being feels. Even if I were sitting opposite you, dear reader, drinking coffee, I could only try to guess what you are feeling. And this despite the fact that we belong to the same species. And yet: the data seems clear, fish are capable of astonishing mental and emotional achievements.
Going to the fish counter and ordering fish in a restaurant will definitely be more difficult after reading this. This is a side effect of reading this book - and this is undoubtedly what Jonathan Balcombe intended.
The Fish That Recognizes People
The author not only presents scientific studies, he also sprinkles in numerous anecdotes. For example, he tells the story of Rosamonde Cooke, an ecologist who worked at Colorado State University. During the summer holidays, she helped feed the fish in an aquarium, including a young black bass. Rosamonde was convinced that the fish recognized her because it only swam to the edge of the aquarium when she passed by. This was even the case when she was in a crowd. When other people walked past the aquarium, it showed no reaction. The professors at the university, however, believed that fish cannot recognize human faces. Rosamonde, of course, saw things very differently and intuitively anticipated later research results. There is now scientific evidence that some species of fish can recognize human faces. Incidentally, Rosamonde later released the black bass into a large pond on the university grounds, where fishing is prohibited.