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These two types of fish can be counted

These two types of fish can be counted

According to the findings of scientists at the University of Bonn, fish can count, the university announced on Friday. According to the study published in the journal Scientific Reports, fish and stingrays can add and subtract up to five numbers.

Bonn zoologist Vera Schlussel had both species perform simple addition and subtraction operations in her studies. “They had to increase or decrease an initial value by one,” Key explained. To do this, she and her team used methods already tried and tested on other animal species to test mathematical abilities.

Present the fish a set of geometric shapes, such as four squares. If it is colored blue, it means “add one”. Squares colored in yellow mean “Subtract one”.

be rewarded with food

After that, the tasks were hidden and the animals were shown new pictures – one with five and the other with three squares. If they swim to the correct picture – that is, when five blue squares are added instead of four – the fish are rewarded with food. If they answer wrongly, they get nothing.

In order to test whether the fish could also apply their knowledge to new tasks, the researchers changed their tasks after the learning phase. It turns out that the fish can now also solve the tasks three plus one and three minus one. The fish may also have been correctly calculated in a combination of several geometric shapes such as square, triangle and circle.

The researchers were also surprised by the performance of the chick and the rays because they did not have a cerebral cortex. In humans, this is responsible for the most complex cognitive tasks. In addition, the two types of fish are not known to require a good understanding of numbers. The study’s lead, Schlussel, sees the result of her work as confirmation that humans tend to underestimate other species.