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Biology: Frogs can recognize colors even in the dark


Impressive senses: frogs can see colors even in the dark
More and more people have vision problems: only recently was a study published that came to the conclusion that half the world's population could become short-sighted by 2050. In the animal kingdom, however, some species can see particularly well. Among other things, certain birds, as is also made clear by the term "eagle eye". What researchers are now reporting about frogs is impressive: the amphibians can see colors even in the dark.

Extraordinary sensory achievements in the animal kingdom
The sensory organs perform, which often seem unimaginable. The human nose, for example, perceives over a trillion smells. In the animal kingdom, the senses are often much sharper. For example, dogs can not only hear much better than humans, but also smell significantly better. Scientific studies have also shown that the four-legged friend's sense of smell is more intense. For example, Austrian researchers reported that dogs can smell lung cancer. And Japanese scientists found that they can sniff out colon cancer. Trained dogs can also warn of hypoglycemia in diabetes. Frogs are also equipped with very special senses: they can see colors in the dark.

See colors in the dark
Some animals can see very well. For example, the outstanding visual performance of the birds of prey with the proverbial "eagle eye" has entered general awareness.

What frogs are capable of is at least as impressive: you can see colors in the dark, as Swedish, Finnish and Russian researchers have observed.

A communication from the University of Lund (Sweden) says: "The night vision of frogs and toads seems to be superior to that of all other animals."

"They have the ability to see colors, even if it is so dark that people cannot see anything at all," it continues.

Frogs with a unique ability
"We have shown earlier that moths and geckos can see colors in poorer light conditions than humans," explained the biology professor Almut Kelber from the Swedish university.

"But frogs seem to have the unique ability to see colors in the dark."

According to the dpa news agency, the researchers believe that this is due to the animals' special visual cells in the retina. The amphibians - unlike humans, for example - have chopsticks that are sensitive to different degrees, the team writes in the specialist magazine "Philosophical Transactions of the Royal Society B".

For one of their experiments in Helsinki (Finland), the scientists put grass frogs in a dark bucket that had two openings. They put a blue filter on one and a green filter on the other. Through this at first some light shone into the bucket.

"When the frogs are in the dark and see the light, they jump there to get out of the bucket," explained Kelber.

Seeing without light does not work
When the researchers finally let very little light into the bucket, the animals jumped towards the green cover.

"So it could only be the color," says Kelber, according to dpa. “You can ask yourself why they preferred green. But you could imagine that if you are a frog in the dark and want to go to the forest, you’re more likely to jump where it’s green. ”

Scientists are convinced that the common frog can see colors even when it is already completely dark for us humans.

However, it turned out that the frogs could no longer see anything in absolute darkness. "Seeing without light is impossible," says Kelber. "But the frogs still see color with so little light that it is dark for our eyes." The professor said: "These results were unexpected." (Ad)

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