--- description: A photo posted by NASA appears to show spiders crawling on Mars' surface, but it's actually a seasonal process called araneiform terrain. title: A NASA Image Shows 'Spiders' Crawling Over Mars' Surface image: https://static.time.com/v3/assets/bltea6093859af6183b/blt056ea1e0c8bac1db/6989355b656a3f5774bd4f38/spiders-on-mars.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [Science](/section/science/) ## Science Update your preferences in [Account Settings](/account/preferences/) Close * [Space](/tag/space/) ## Space Update your preferences in [Account Settings](/account/preferences/) Close # New NASA Image Shows 'Spiders' Crawling Over Mars' Surface  by [Jamie Ducharme](/author/jamie-ducharme/)  ## Jamie Ducharme Update your preferences in [Account Settings](/account/preferences/) Close Ducharme is a contributor to TIME. Jul 14, 2018 3:04 PM CUT  NASA/JPL-Caltech/Univ. of Arizona  by [Jamie Ducharme](/author/jamie-ducharme/)  ## Jamie Ducharme Update your preferences in [Account Settings](/account/preferences/) Close Ducharme is a contributor to TIME. Jul 14, 2018 3:04 PM CUT An image captured by NASA’s Mars Reconnaissance Orbiter appears to show spiders crawling over the surface of the Red Planet — but, in this case, appearances are deceiving. The photo, was originally taken on May 13 and [posted as NASA’s image of the day](https://www.nasa.gov/image-feature/jpl/jamming-with-the-spiders-from-mars "undefined") on Thursday. It actually shows “araneiform terrain,” a phenomenon that happens when carbon dioxide below Mars’ surface warms in the spring and changes from solid to gas, leaving gas trapped beneath the planet’s surface. As pressure builds, the gas eventually bursts through the surface to release dust that either gathers around the vent or is blown away by the wind. The results are the spider-like features captured by the Reconnaissance Orbiter. “There are radially organized channels on Mars that look spider-like, but we don’t want to confuse anyone by talking about ‘spiders’ when we really mean ‘channels,’ not ‘bugs,'” [representatives from NASA wrote](https://www.nasa.gov/mission%5Fpages/MRO/multimedia/pia10141.html "undefined"). This seasonal process doesn’t happen on earth, but NASA likened the phenomenon to the properties of dry ice on our planet. ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/5338788/spiders-mars-araneiform-terrain/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/5338788/spiders-mars-araneiform-terrain/"},"headline":"New NASA Image Shows 'Spiders' Crawling Over Mars' Surface","datePublished":"2018-07-14T15:04:47.000Z","dateModified":"2026-02-23T20:50:59.765Z","description":"It's actually araneiform terrain","url":"https://time.com/5338788/spiders-mars-araneiform-terrain/","keywords":["Space","onetime"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/blt056ea1e0c8bac1db/6989355b656a3f5774bd4f38/spiders-on-mars.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jamie Ducharme","jobTitle":"Ducharme is a contributor to TIME.","url":"https://time.com/author/jamie-ducharme/"}],"articleSection":"Science","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/blt056ea1e0c8bac1db/6989355b656a3f5774bd4f38/spiders-on-mars.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"spiders-on-mars","caption":"spiders-on-mars","creditText":"NASA/JPL-Caltech/Univ. of Arizona","representativeOfPage":true}],"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":"/tag/space/","name":"Space"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/5338788/spiders-mars-araneiform-terrain/","name":"New NASA Image Shows 'Spiders' Crawling Over Mars' Surface"}}]}] ```