--- description: Scientists use a new underwater microscope to observe coral in its natural habitat for the first time. title: New Microscope Shows Coral Colonies Kissing, Fighting and Eating image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production --- * [Science](/section/science/) ## Science Update your preferences in [Account Settings](/account/preferences/) Close # New Microscope Shows Coral Colonies Kissing, Fighting and Eating by [Marisa Gertz](/author/marisa-gertz/) ## Marisa Gertz Update your preferences in [Account Settings](/account/preferences/) Close Jul 14, 2016 4:42 PM CUT by [Marisa Gertz](/author/marisa-gertz/) ## Marisa Gertz Update your preferences in [Account Settings](/account/preferences/) Close Jul 14, 2016 4:42 PM CUT Although [corals](http://oceanservice.noaa.gov/education/tutorial%5Fcorals/coral01%5Fintro.html "undefined") look like a plant, they are actually animals, made up of thousands of individual polyps living together in a colony. Because of their small size, scientific observation of them has been difficult, if not impossible outside of a lab. Now, Andrew Mullen and Tali Treibitz from the University of California San Diego have developed a new way to observe [coral colonies](http://time.com/4292505/great-barrier-reef-climate-change/ "undefined") in their natural habitat. The Benthic Underwater Microscope (BUM) allows divers to capture photos of corals over time without removing samples to be studied in a lab, as they demonstrated in a paper published in [Nature](http://www.nature.com/ncomms/2016/160712/ncomms12093/full/ncomms12093.html "undefined") on July 12th. They used the BUM in the Gulf of Eilat at the northern tip of the Red Sea to observe corals feeding, fighting, sharing, and even ‘kissing’, a previously unobserved behavior. As [coral bleaching](http://time.com/4375553/coral-reefs-bleaching-climate-change/ "undefined") threatens the world’s [reefs](http://time.com/4313908/coral-reef-global-warming-climate-change-miami/ "undefined"), they hope that the instrument will be an important tool in understanding how corals work in the complex and constantly changing environment of the sea floor. ### Kissing  Andrew D. Mullen; Gif by Marisa Gertz for TIME Two polyps connect their gastrovascular openings at night, a behavior that has never been documented before. Dubbed ‘polyp kissing,’ this behavior likely allows the polyps to exchange materials, such as food. ### Communal feeding  Andrew D. Mullen; Gif by Marisa Gertz for TIME Scientists injected Artemia, a brine shrimp, near the coral and captured a time-lapse video of communal feeding between two neighboring polyps. The two polyps work together by intertwining their tentacles to digest their prey. ### Competition with Pocillopora  Andrew D. Mullen; Gif by Marisa Gertz for TIME Two different loose corals colonies, Stylophora on the left and Pocillopora on the right were placed close together to induce competition. When corals compete for dominance, they emit mesenterial filaments, string-like structures, which they use to attack and, ultimately, digest their rival. ### Competition with Platygyra  Andrew D. Mullen; Gif by Marisa Gertz for TIME Here, the Platygyra, on the left, has attacked and is beginning to digest the Stylophora, on the right. Scientists found that competition response times and attack mechanisms differed depending on the coral. When a Platygyra was placed next to one of its own kind, for example, it did not attack at all. ### Brine shrimp  Andrew D. Mullen; Gif by Marisa Gertz for TIME A Platygyra colony extends its filaments when exposed to a net filled with brine shrimp, right. Colonies were exposed to a number of different stimuli in order to record their responses. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/4406312/coral-colonies-microscope-kissing-eating-fighting/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/4406312/coral-colonies-microscope-kissing-eating-fighting/"},"headline":"New Microscope Shows Coral Colonies Kissing, Fighting and Eating","datePublished":"2016-07-14T16:42:55.000Z","dateModified":"2026-05-11T04:59:46.550Z","description":"Coral likes to kiss too","url":"https://time.com/4406312/coral-colonies-microscope-kissing-eating-fighting/","keywords":["Science topic"],"thumbnailUrl":"","author":[{"@type":"Person","name":"Marisa Gertz","jobTitle":null,"url":"https://time.com/author/marisa-gertz/"}],"articleSection":"Science","image":[],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/science/","name":"Science"}},{"@type":"ListItem","position":2,"item":{"@id":"https://time.com/4406312/coral-colonies-microscope-kissing-eating-fighting/","name":"New Microscope Shows Coral Colonies Kissing, Fighting and Eating"}}]}] ```