The Skin That Sees

The fourth morning, Chiara was running late. She came in with two coffees from the corner bar. "We have not done the colour test for Polly," she said.

Štvrté ráno Chiara meškala. Prišla s dvoma kávami z baru na rohu. "Ešte sme neurobili farebný test pre Polly," povedala.

She put three plates on the tank floor. Bright red. Bright blue. Bright yellow. Under one of them, a small dome covered a piece of shrimp. Today, the shrimp was under the red plate.

Položila tri taniere na dno nádrže. Jasne červený. Jasne modrý. Jasne žltý. Pod jedným z nich bola malá kupola, ktorá zakrývala kúsok krevety. Dnes bola kreveta pod červeným tanierom.

"Here is the strange thing," Chiara said. "Octopuses are colour-blind. Their eyes have only one kind of photoreceptor. By every test we have ever done on their eyes, they cannot tell colours apart."

"Tu je tá zvláštnosť," povedala Chiara. "Chobotnice sú farboslepé. Ich oči majú len jeden druh fotoreceptoru. Podľa všetkých testov, ktoré sme kedy robili na ich očiach, nemôžu rozlíšiť farby."

Polly tilted her head.

Polly naklonila hlavu.

"And yet," Chiara said. "Watch."

"A predsa," povedala Chiara. "Sleduj."

Pasta uncurled. Two arms went out across the tank floor. They passed over the blue plate without slowing. They passed over the yellow plate without slowing. They paused over the red plate. One arm lifted the dome. Pasta took the shrimp.

Pasta sa rozvinula. Dve ramená sa natiahli cez dno nádrže. Prešli cez modrý tanier bez spomalenia. Prešli cez žltý tanier bez spomalenia. Zastavili sa nad červeným tanierom. Jedno rameno zdvihlo kupolu. Pasta si vzala krevetu.

"She is not blind to colour," Chiara said. "But it is not her eyes that see it."

"Nie je slepá na farby," povedala Chiara. "Ale nie sú to jej oči, ktoré to vidia."

In the last fifteen years, biologists have discovered that octopus skin is full of light-sensing cells. The same molecules that line a human retina line the surface of an octopus arm. The skin can detect different wavelengths of light. In some species, the skin can detect specific colours.

Za posledných pätnásť rokov biológovia zistili, že koža chobotnice je plná buniek citlivých na svetlo. Rovnaké molekuly, ktoré lemujú ľudskú sietnicu, lemujú povrch ramena chobotnice. Koža dokáže detekovať rôzne vlnové dĺžky svetla. U niektorých druhov dokáže koža detekovať špecifické farby.

This is one answer to an old puzzle: how does a colour-blind animal camouflage itself perfectly into colourful environments? An octopus on coral matches the coral. An octopus on sand matches the sand. Its eyes cannot see colour. But its skin can. The skin sees what the skin needs to copy.

Toto je jedna odpoveď na starú hádanku: ako sa farboslepé zviera dokonale maskuje v pestrofarebnom prostredí? Chobotnica na koraloch sa zhoduje s koralmi. Chobotnica na piesku sa zhoduje s pieskom. Jej oči nevidia farbu. Ale jej koža áno. Koža vidí, čo potrebuje napodobniť.

Polly walked along the rim of the tank slowly. She had never thought about her own eyes before. The idea that an animal could see with parts of itself other than its eyes was strange.

Polly pomaly kráčala po okraji nádrže. Nikdy predtým nepremýšľala o svojich vlastných očiach. Myšlienka, že zviera môže vidieť časťami svojho tela inými ako očami, bola zvláštna.

"We have published papers on this for a decade," Chiara said. "Most people still cannot believe it. The animal's skin sees."

"Publikovali sme o tom články už desať rokov," povedala Chiara. "Väčšina ľudí tomu stále nemôže uveriť. Koža zvieraťa vidí."