The Skin That Sees

The fourth morning, Chiara was running late. She came in carrying two coffees from the bar on the corner and her hair was wet from the sea breeze. She set one coffee on the counter. "I had a thought last night," she said. "We have not done the colour test for Polly."

Četvrtog jutra, Chiara je kasnila. Ušla je noseći dvije kave iz bara na uglu, a kosa joj je bila mokra od morskog povjetarca. Jednu kavu stavila je na pult. "Sinoć sam imala jednu misao," rekla je. "Nismo napravili test boje za Polly."

The colour test was Pasta's favourite, Chiara said. She set out three flat plates of different colours on the tank floor. Bright red. Bright blue. Bright yellow. On one of them, under a small plastic dome, was a piece of shrimp. Today, the shrimp was under the red plate.

Test boje bio je Pastin omiljeni, rekla je Chiara. Postavila je tri plitka tanjura različitih boja na dno akvarija. Jarko crvena. Jarko plava. Jarko žuta. Na jednom od njih, ispod male plastične kupole, bio je komadić škampi. Danas su škampi bili ispod crvenog tanjura.

"Here is the thing," Chiara said. "Octopuses are colour-blind. Their eyes have only one kind of photoreceptor, not three the way ours do. By every test we have ever done on their eyes alone, octopuses cannot distinguish colours."

"Evo u čemu je stvar," rekla je Chiara. "Hobotnice su daltonisti. Njihove oči imaju samo jednu vrstu fotoreceptora, a ne tri kao naše. Prema svakom testu koji smo ikada napravili samo na njihovim očima, hobotnice ne mogu razlikovati boje."

Polly tilted her red head.

Polly je nagnula svoju crvenu glavu.

"And yet," Chiara said. She pointed at the tank. "Watch."

"Ipak," rekla je Chiara. Pokazala je na akvarij. "Gledaj."

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 se odmotala. Dvije ruke pružile su se preko dna akvarija. Prošle su preko plavog tanjura bez usporavanja. Prošle su preko žutog tanjura bez usporavanja. Zastale su iznad crvenog tanjura. Jedna ruka podigla je kupolu. Pasta je uzela škampe.

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

"Nije slijepa na boje," rekla je Chiara. "Ali nisu njezine oči te koje ih vide."

In the last fifteen years, biologists have discovered that the skin of an octopus is full of light-sensing cells called opsins. The same molecule that lines a human retina lines the entire surface of an octopus arm. The octopus's skin can detect light at different wavelengths. In some species, the skin can detect specific colours.

U posljednjih petnaest godina, biolozi su otkrili da je koža hobotnice puna stanica osjetljivih na svjetlost, zvanih opsini. Ista molekula koja oblaže ljudsku mrežnicu oblaže cijelu površinu hobotničine ruke. Koža hobotnice može detektirati svjetlost na različitim valnim duljinama. Kod nekih vrsta, koža može detektirati specifične boje.

This is one possible answer to a question that had puzzled biologists for a hundred years: how does a colour-blind animal camouflage itself so 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.

Ovo je jedan mogući odgovor na pitanje koje je zbunjivalo biologe stotinu godina: kako se daltonistička životinja kamuflira tako savršeno u šarene okoline? Hobotnica na koralju odgovara koralju. Hobotnica na pijesku odgovara pijesku. Njene oči ne mogu vidjeti boju. Ali njena koža može. Koža vidi ono što koža treba kopirati.

Pasta withdrew with her shrimp. The whole experiment had taken under a minute.

Pasta se povukla sa svojim škampima. Cijeli eksperiment trajao je manje od minute.

Polly walked along the rim of the tank slowly. She had never thought about her own eyes before. She had simply trusted them. The idea that an animal could see with parts of itself other than its eyes was, for a moment, deeply strange. She thought, with the small flutter of vertigo it deserved, that she had no idea what most of her own body knew.

Polly je polako hodala uz rub akvarija. Nikada prije nije razmišljala o vlastitim očima. Jednostavno im je vjerovala. Ideja da životinja može vidjeti dijelovima sebe koji nisu oči bila je, na trenutak, duboko čudna. Pomislila je, s malim drhtajem vrtoglavice koji je to zaslužio, da nema pojma što većina njezina tijela zna.

Chiara picked up her coffee. "It is interesting, no?"

Chiara je podigla svoju kavu. "Zanimljivo je, zar ne?"

Polly tilted her red head.

Polly je nagnula svoju crvenu glavu.

"There is more," Chiara said. "We have published papers on this for a decade. Most people still cannot believe it. The animal's skin sees." She drank the coffee. "Welcome to the part of biology where we don't actually know much."

"Ima još," rekla je Chiara. "Već desetljeće objavljujemo radove o tome. Većina ljudi još uvijek ne može vjerovati. Koža životinje vidi." Popila je kavu. "Dobrodošli u dio biologije gdje zapravo ne znamo mnogo."