Ngozi Inayoona

Asubuhi ya nne, Chiara alikuwa amechelewa. Aliingia akiwa amebeba kahawa mbili kutoka kwenye baa ya kona na nywele zake zilikuwa zenye unyevunyevu kutokana na upepo wa baharini. Aliweka kikombe kimoja cha kahawa kwenye kaunta. "Nilikuwa na wazo jana usiku," alisema. "Hatujafanya jaribio la rangi kwa Polly."

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."

Jaribio la rangi lilikuwa kipenzi cha Pasta, alisema Chiara. Aliweka sahani tatu bapa za rangi tofauti kwenye sakafu ya tanki. Nyekundu angavu. Bluu angavu. Njano angavu. Kwenye moja ya hizo, chini ya dome ndogo ya plastiki, kulikuwa na kipande cha kamba. Leo, kamba ilikuwa chini ya sahani nyekundu.

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.

"Hapa ndipo jambo lilipo," alisema Chiara. "Pweza hawaoni rangi. Macho yao yana aina moja tu ya kipokezi mwanga, si tatu kama yetu. Kulingana na kila jaribio tulilowahi kufanya kwa macho yao pekee, pweza hawawezi kutofautisha rangi."

"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."

Polly alitikisa kichwa chake chekundu.

Polly tilted her red head.

"Na bado," Chiara alisema. Alielekeza kidole kwenye tanki. "Tazama."

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

Pasta alijikunja. Mikono miwili ilielekea kwenye sakafu ya tanki. Ilipita juu ya sahani ya bluu bila kusita. Ilipita juu ya sahani ya njano bila kusita. Ilisimama juu ya sahani nyekundu. Mkono mmoja uliinua dome. Pasta alichukua kamba.

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.

"Haoni rangi kwa macho," Chiara alisema. "Lakini si macho yake yanayoona rangi."

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

Katika miaka kumi na tano iliyopita, wanabiolojia wamegundua kuwa ngozi ya pweza imejaa seli za kuhisi mwanga zinazoitwa opsins. Molekuli ile ile inayopanga retina ya binadamu inapanga uso mzima wa mkono wa pweza. Ngozi ya pweza inaweza kugundua mwanga katika mawimbi tofauti. Katika baadhi ya spishi, ngozi inaweza kugundua rangi maalum.

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.

Hii ni jibu moja linalowezekana kwa swali lililowachanganya wanabiolojia kwa miaka mia moja: jinsi gani mnyama asiyeona rangi anaweza kujificha kikamilifu katika mazingira yenye rangi nyingi? Pweza aliye juu ya matumbawe anafanana na matumbawe. Pweza aliye juu ya mchanga anafanana na mchanga. Macho yake hayaoni rangi. Lakini ngozi yake inaweza. Ngozi inaona kile ambacho ngozi inahitaji kuiga.

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.

Pasta alijiondoa na kamba yake. Jaribio lote lilichukua chini ya dakika moja.

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

Polly alitembea kando ya ukingo wa tanki polepole. Hakuwahi kufikiria kuhusu macho yake mwenyewe hapo awali. Aliyaamini tu. Wazo kwamba mnyama anaweza kuona kwa sehemu nyingine za mwili wake zaidi ya macho lilikuwa, kwa muda mfupi, la ajabu sana. Alifikiria, kwa mhemko mdogo wa kizunguzungu uliostahili, kwamba hakuwa na wazo lolote kuhusu kile ambacho sehemu kubwa ya mwili wake mwenyewe inajua.

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.

Chiara alichukua kahawa yake. "Inavutia, sivyo?"

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

Polly alitikisa kichwa chake chekundu.

Polly tilted her red head.

"Kuna zaidi," Chiara alisema. "Tumechapisha makala kuhusu hili kwa muongo mmoja. Watu wengi bado hawawezi kuamini. Ngozi ya mnyama inaona." Alikunywa kahawa. "Karibu kwenye sehemu ya biolojia ambapo hatujui mengi sana."

"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."