One fish, two fish: Fish can count, and the discovery can help us do math

“Fish are on par with other animals in possessing a sense of quantity,” said Prof. Giorgio Vallortigara from the University of Trento, Italy, corresponding author of the study.

Fish are seen swimming below the Mediterranean Sea, where climate change has forced many animals to swim to new depths. (photo credit: Dr. Shevy Rothman)
Fish are seen swimming below the Mediterranean Sea, where climate change has forced many animals to swim to new depths.
(photo credit: Dr. Shevy Rothman)

A new peer-reviewed study published on Thursday in Frontiers in Neuroanatomy found that fish are able to determine quantities with similar parts of the brain as birds and mammals, a discovery that could help researchers find how the brain calculates math and in turn, enable the treatment of diseases that impair the ability to do math.

“Fish are on par with other animals in possessing a sense of quantity,” said Prof. Giorgio Vallortigara from the University of Trento, Italy, corresponding author of the study. “There are species, most notably the zebrafish, that are ideal models for studying the molecular and genetic bases of the sense of quantity. This could have important implications for neurodevelopmental diseases affecting number cognition, such as developmental dyscalculia, which impairs maths skills in up to 6% of children.”

The researchers found through behavioral studies that the ability of fish to discern between larger and smaller amounts of food is comparable to that of birds and mammals, a trait that is essential for survival.

While previous studies have also used fish behavior to find how they determine quantity, the new study found that it was necessary to observe the process at a cellular and genetic level.

The researchers used brain imaging in order to show that fish use similar parts of the brain as many other vertebrates.

Fish illustrative (credit: Courtesy)Fish illustrative (credit: Courtesy)

Vallortigara's remarks

“Another open issue is whether numerical quantities are really computed as an abstract property or whether animals always think about numbers on the basis of other cues from their surroundings (such as surface area, contour length, or density). However, experiments are described in this review that show that pure numerousness is indeed used by fish.”

Prof. Giorgio Vallortigara, corresponding author, University of Trento

“Another open issue is whether numerical quantities are really computed as an abstract property or whether animals always think about numbers on the basis of other cues from their surroundings (such as surface area, contour length, or density),” Vallortigara noted. “However, experiments are described in this review that show that pure numerousness is indeed used by fish.”