Freshwater Fish Can Do Math, New Study Suggests

A researcher from University of California, Davis catches hatchery salmon from a tank to measure their size, as part of a joint project between ecologists and rice farmers trying to reclaim the great flood plains of the Sacramento River for salmon habitat, in Robbins, California, US, February 4, 2022. REUTERS/Carlos Barria
A researcher from University of California, Davis catches hatchery salmon from a tank to measure their size, as part of a joint project between ecologists and rice farmers trying to reclaim the great flood plains of the Sacramento River for salmon habitat, in Robbins, California, US, February 4, 2022. REUTERS/Carlos Barria
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Freshwater Fish Can Do Math, New Study Suggests

A researcher from University of California, Davis catches hatchery salmon from a tank to measure their size, as part of a joint project between ecologists and rice farmers trying to reclaim the great flood plains of the Sacramento River for salmon habitat, in Robbins, California, US, February 4, 2022. REUTERS/Carlos Barria
A researcher from University of California, Davis catches hatchery salmon from a tank to measure their size, as part of a joint project between ecologists and rice farmers trying to reclaim the great flood plains of the Sacramento River for salmon habitat, in Robbins, California, US, February 4, 2022. REUTERS/Carlos Barria

Some primates, bees, birds, and now freshwater fish: the circle of animals with mathematical skills is widening. A recent study has found that some types of fish have mathematical abilities such as addition.

It’s scientifically proven that all vertebrates, and even some invertebrates have the ability to measure quantities- a vital function creatures need when searching for food, avoiding predators, moving in group, and mating.

But scientists are now investigating how these creatures can quantify: is it a simple estimate based of the object’s size, or they are actually able of doing accurate math? Former studies showed that some monkeys, parrots, pigeons, spiders, and bees are capable of processing numerical information, and even performing simple mathematical functions.

A recent study at the University of Bonn’s Institute of Zoology revealed that some types of fish such as cichlids, stingrays, and zebra mbuna have some math skills. The findings were published in the journal Scientific Reports.

Eight fish of each type underwent hundreds of tests in large tanks specially designed to monitor their performance. In the tanks, the fish were trained to associate the blue color with addition (+1), and the yellow color with subtraction (-1).

Then, the scientists spread cards featuring blue and yellow shapes, and made the fish choose from two sliding doors each featuring a card with different number of shapes; one of the two doors has the correct answer.

For instance, when a fish sees a card with three blue shapes, it is supposed to swim towards the door with the card featuring four blue shapes as blue refers to addition. On the contrary, if the fish sees a card featuring four yellow shapes, it should head towards the door with the card featuring three yellow shapes, one shape lesser than the original card, as yellow refers to subtraction.

When the fish passed through the correct door, it was rewarded with its favorite food. The study showed that six of the mbuna fish and four stingrays successfully linked blue to (+1), and yellow to (-1).

According to researchers, the mbuna fish needed more time to select the door, and mbunas and stingrays remembered addition more easily than subtraction.

The researchers said their work unveils new cognitive abilities that could help mbunas and stingrays recognize other fishes from the same species based on their appearance, by counting the lines or spots on their bodies.



Hungary's Oldest Library is Fighting to Save Books from Beetle Infestation

Books are kept in hermetically sealed plastic sacks for disinfection at the Pannonhalma Archabbey's library in Pannonhalma, Hungary, Thursday, July 3, 2025, as a beetle infestation threatens its ancient collection. (AP Photo/Bela Szandelszky)
Books are kept in hermetically sealed plastic sacks for disinfection at the Pannonhalma Archabbey's library in Pannonhalma, Hungary, Thursday, July 3, 2025, as a beetle infestation threatens its ancient collection. (AP Photo/Bela Szandelszky)
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Hungary's Oldest Library is Fighting to Save Books from Beetle Infestation

Books are kept in hermetically sealed plastic sacks for disinfection at the Pannonhalma Archabbey's library in Pannonhalma, Hungary, Thursday, July 3, 2025, as a beetle infestation threatens its ancient collection. (AP Photo/Bela Szandelszky)
Books are kept in hermetically sealed plastic sacks for disinfection at the Pannonhalma Archabbey's library in Pannonhalma, Hungary, Thursday, July 3, 2025, as a beetle infestation threatens its ancient collection. (AP Photo/Bela Szandelszky)

Tens of thousands of centuries-old books are being pulled from the shelves of a medieval abbey in Hungary in an effort to save them from a beetle infestation that could wipe out centuries of history.

The 1,000-year-old Pannonhalma Archabbey is a sprawling Benedictine monastery that is one of Hungary's oldest centers of learning and a UNESCO World Heritage site.

Restoration workers are removing about 100,000 handbound books from their shelves and carefully placing them in crates, the start of a disinfection process that aims to kill the tiny beetles burrowed into them, The Associated Press reported.

The drugstore beetle, also known as the bread beetle, is often found among dried foodstuffs like grains, flour and spices. But they also are attracted to the gelatin and starch-based adhesives found in books.

They have been found in a section of the library housing around a quarter of the abbey's 400,000 volumes.

“This is an advanced insect infestation which has been detected in several parts of the library, so the entire collection is classified as infected and must be treated all at the same time,” said Zsófia Edit Hajdu, the chief restorer on the project. “We've never encountered such a degree of infection before.”

The beetle invasion was first detected during a routine library cleaning.

Employees noticed unusual layers of dust on the shelves and then saw that holes had been burrowed into some of the book spines. Upon opening the volumes, burrow holes could be seen in the paper where the beetles chewed through.

The abbey at Pannonhalma was founded in 996, four years before the establishment of the Kingdom of Hungary. Sitting upon a tall hill in northwestern Hungary, the abbey houses the country's oldest collection of books, as well as many of its earliest and most important written records.

For over 1,000 years, the abbey has been among the most prominent religious and cultural sites in Hungary and all of Central Europe, surviving centuries of wars and foreign incursions such as the Ottoman invasion and occupation of Hungary in the 16th century.

Ilona Ásványi, director of the Pannonhalma Archabbey library, said she is “humbled” by the historical and cultural treasures the collection holds whenever she enters.

“It is dizzying to think that there was a library here a thousand years ago, and that we are the keepers of the first book catalogue in Hungary,” she said.

Among the library’s most outstanding works are 19 codices, including a complete Bible from the 13th century. It also houses several hundred manuscripts predating the invention of the printing press in the mid-15th century and tens of thousands of books from the 16th century.

While the oldest and rarest prints and books are stored separately and have not been infected, Ásványi said any damage to the collection represents a blow to cultural, historical and religious heritage.

“When I see a book chewed up by a beetle or infected in any other way, I feel that no matter how many copies are published and how replaceable the book is, a piece of culture has been lost,” she said.

To kill the beetles, the crates of books are being placed into tall, hermetically sealed plastic sacks from which all oxygen is removed. After six weeks in the pure nitrogen environment, the abbey hopes all the beetles will be destroyed.

Before being reshelved, each book will be individually inspected and vacuumed. Any book damaged by the pests will be set aside for later restoration work.

The abbey, which hopes to reopen the library at the beginning of next year, believes the effects of climate change played a role in spurring the beetle infestation as average temperatures rise rapidly in Hungary.

Hajdu, the chief restorer, said higher temperatures have allowed the beetles to undergo several more development cycles annually than they could in cooler weather.

“Higher temperatures are favorable for the life of insects,” she said. “So far we've mostly dealt with mold damage in both depositories and in open collections. But now I think more and more insect infestations will appear due to global warming.”

The library’s director said life in a Benedictine abbey is governed by a set of rules in use for nearly 15 centuries, a code that obliges them to do everything possible to save its vast collection.

“It says in the Rule of Saint Benedict that all the property of the monastery should be considered as of the same value as the sacred vessel of the altar,” Ásványi said. “I feel the responsibility of what this preservation and conservation really means.”