{"id":30656,"date":"2026-08-01T08:50:00","date_gmt":"2026-08-01T12:50:00","guid":{"rendered":"https:\/\/www.ecoportal.net\/en\/?p=30656"},"modified":"2026-08-01T08:50:00","modified_gmt":"2026-08-01T12:50:00","slug":"coral-reef-creature-photoreceptors-took-color","status":"publish","type":"post","link":"https:\/\/www.ecoportal.net\/en\/coral-reef-creature-photoreceptors-took-color\/30656\/","title":{"rendered":"Biologists gave a mantis shrimp with 12 color receptors the same test they give humans with 3, and the animal could not tell apart shades a honeybee separates without trouble"},"content":{"rendered":"<p>Every few years the same animal goes around the internet again.<\/p>\n<p>The claim is always that it sees colors we cannot imagine, and that human vision beside it is&nbsp;<strong>a smudged photocopy<\/strong>.<\/p>\n<p>The arithmetic behind that story is real. We run on three types of color receptor, and this one carries&nbsp;<strong>four times as many<\/strong>.<\/p>\n<p>So a team in Australia finally&nbsp;<strong>sat the animal down<\/strong>&nbsp;and tested it properly.<\/p>\n<p>It failed, and it failed by a margin nobody had prepared for.<\/p>\n<h2>What the twelve receptors actually are<\/h2>\n<p>The creature is a mantis shrimp, a stomatopod that lives in a burrow on tropical reefs and punches hard enough to crack aquarium glass.<\/p>\n<p>Its eyes sit on stalks and move independently, each one split by a band of specialized rows across the middle.<\/p>\n<p>Those rows hold&nbsp;<strong>12 color receptor types<\/strong>, eight covering the visible spectrum and four reaching into the ultraviolet.<\/p>\n<p>Human eyes hold three, tuned to broad and heavily overlapping ranges of wavelength.<\/p>\n<p>Our brains then compare the output of those three against one another, and everything you have ever seen comes out of that comparison.<\/p>\n<p>So four times the hardware sounds like it should mean&nbsp;<strong>four times the world<\/strong>.<\/p>\n<p>That assumption sat in textbooks for roughly twenty five years&nbsp;<strong>without anyone testing it<\/strong>.<\/p>\n<h2>The test that ended the legend<\/h2>\n<p>Then researchers at the University of Queensland built the experiment that should have run decades earlier.<\/p>\n<p>They worked with a small species called Haptosquilla trispinosa, which matters, because it is not the flamboyant peacock species in every photograph.<\/p>\n<p>The animals were trained to strike the glowing tip of a fiber optic cable showing one color, and were fed when they got it right.<\/p>\n<p>Then a second cable appeared, and its color was&nbsp;<strong>walked steadily closer<\/strong>&nbsp;to the first.<\/p>\n<p>The point where it stopped choosing correctly is the discrimination threshold.<\/p>\n<p>Two shades had to sit&nbsp;<strong>15 to 25 nanometers<\/strong>&nbsp;apart before a mantis shrimp reliably noticed any difference.<\/p>\n<p>A human manages between one and five, and a honeybee with far fewer receptors does better than the shrimp too.<\/p>\n<p>The animal with the most celebrated eye in the ocean came in&nbsp;<strong>near the bottom<\/strong>.<\/p>\n<h2>What the eye is doing instead<\/h2>\n<p>Which is the interesting part, because failing that test is not the same as seeing badly.<\/p>\n<p>It means the eye was never built to do what our eyes do.<\/p>\n<p>We compare receptors and assemble a picture, and that comparison takes brain tissue and it takes time.<\/p>\n<p>A stomatopod appears to skip the assembly entirely, sweeping its eye across an object and reading each of the twelve channels&nbsp;<strong>as a fixed value<\/strong>.<\/p>\n<p>Justin Marshall, who led the work, compares the setup to a satellite rather than to an eye, since remote sensing runs on lookup tables that match a signal to an answer without building a scene.<\/p>\n<p>The result is&nbsp;<strong>recognition without interpretation<\/strong>, which on a reef is worth more than richness.<\/p>\n<p>Because a burrow entrance offers about&nbsp;<strong>one second to decide<\/strong>&nbsp;whether the shape in front of you is a mate, a rival or a meal.<\/p>\n<h2>The parts of the legend that survived<\/h2>\n<p>None of this makes the eye ordinary, and two findings since have made it stranger.<\/p>\n<p>A team at the University of Maryland sequenced what those eyes express and found&nbsp;<strong>at least 33<\/strong>&nbsp;light sensitive proteins, roughly double the sixteen anyone had expected.<\/p>\n<p>Nobody yet knows what most of them are for, which is an unusual sentence to write about an animal this heavily studied, and the original Queensland result holds up as&nbsp;<a href=\"https:\/\/www.science.org\/doi\/10.1126\/science.1245824\" target=\"_blank\" rel=\"noopener\">the study<\/a>&nbsp;reported it.<\/p>\n<p>Then there is polarization, where the creature has&nbsp;<strong>no competition at all<\/strong>.<\/p>\n<p>It is the only animal ever shown to detect&nbsp;<strong>circularly polarized light<\/strong>, a property most people encounter only in 3D cinema glasses.<\/p>\n<p>Some species carry circularly polarized patches on their bodies and appear to signal each other on a private channel nothing else can read.<\/p>\n<p>The gap between a headline number and what a system actually delivers turns up in other places too, whether the argument is over a&nbsp;<a href=\"https:\/\/ecoportal.net\/en\/fox-lost-wild-home-solar-panels\/24938\/\" target=\"_blank\" rel=\"noopener\">solar site<\/a>&nbsp;or an&nbsp;<a href=\"https:\/\/ecoportal.net\/en\/an-offshore-wind-farm-in-the-north-sea\/28240\/\" target=\"_blank\" rel=\"noopener\">offshore project<\/a>.<\/p>\n<h2>Where engineers are copying it<\/h2>\n<p>So the useful lesson turned out to be the opposite of the meme.<\/p>\n<p>Evolution did not build a better version of our eye. It built&nbsp;<strong>a different instrument<\/strong>, optimized for speed and for a kind of light we ignore.<\/p>\n<p>Engineers noticed. A group at the University of Illinois built a sensor modeled on the stomatopod retina that reads color and polarization in the same frame.<\/p>\n<p>Fitted to a colonoscope, it can pick out the disordered structure of cancerous tissue, and the chip costs&nbsp;<strong>under a hundred dollars<\/strong>, according to&nbsp;<a href=\"https:\/\/news.illinois.edu\/mantis-shrimp-inspired-camera-enables-glimpse-into-hidden-world\/\" rel=\"nofollow noopener\" target=\"_blank\">the university<\/a>.<\/p>\n<p>British researchers found something else in the same eye, a natural filter that outperforms the equivalent part inside&nbsp;<strong>CD and DVD players<\/strong>.<\/p>\n<p>The animal never saw a rainbow we cannot see.<\/p>\n<p>It carries a sensor built for a job we do not have, which is a stranger fact than the one the internet keeps repeating.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Every few years the same animal goes around the internet again. The claim is always that it sees colors we cannot imagine, and that human vision beside it is&nbsp;a smudged photocopy. The arithmetic behind that story is real. We run on three types of color receptor, and this one carries&nbsp;four times as many. So a &#8230; <a title=\"Biologists gave a mantis shrimp with 12 color receptors the same test they give humans with 3, and the animal could not tell apart shades a honeybee separates without trouble\" class=\"read-more\" href=\"https:\/\/www.ecoportal.net\/en\/coral-reef-creature-photoreceptors-took-color\/30656\/\" aria-label=\"Read more about Biologists gave a mantis shrimp with 12 color receptors the same test they give humans with 3, and the animal could not tell apart shades a honeybee separates without trouble\">Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":30953,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"coral reef creature","rank_math_title":"Biologists gave a mantis shrimp with 12 color receptors the same test they give humans with 3, and the animal could not tell apart shades a honeybee separates without trouble","rank_math_description":"Mantis shrimp eyes have 16 photoreceptors versus our 3, yet science found they're surprisingly poor at telling colors apart. The reason why is a genuine w","footnotes":""},"categories":[83],"tags":[],"class_list":["post-30656","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earth"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/30656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=30656"}],"version-history":[{"count":0,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/30656\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/30953"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=30656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=30656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=30656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}