AssetID: 55686454
Headline: Sleazy riders: Fish are hitching a lift by shoving themselves up manta rays' bums
Caption: **VIDEO AVAILABLE: CONTACT INFO@COVERMG.COM TO RECEIVE** BY MARK WORGAN The remora may be the ocean’s rudest hitchhiker as it cruises the seas from an odd perch - up a manta ray’s bum. The little suckerfish from the family Echeneidae has been known to spend its life glued to whales, sharks, and turtles, bagging free transport and the occasional snack while offering a spot of marine “cleaning” in return. But according to a jaw-dropping new study published in Ecology and Evolution, these fishy hitchhikers have now been caught hiding somewhere rather more intimate when it comes to manta rays. Bizarrely, the impertinent fish lodge themselves inside the unfortunate rays’ backsides. Marine researchers reviewing more than a decade of underwater footage from places including Florida and the Maldives discovered the slippery stowaways diving head-first into manta rays’ cloacas - the all-purpose opening used for both waste and reproduction. “Here we report seven observations of Echeneidae cloacal diving behavior in manta rays,” the scientists, led by Emily A. Yeager of the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science comment in their paper. “These observations span all three currently described species of manta rays (Mobula yarae, Mobula birostris, and Mobula alfredi), demonstrate that large Echeneidae can perform cloacal diving behavior in both juvenile and adult manta rays, and show that this behavior occurs across multiple ocean basins.” Typically, remoras hitch lifts using a built-in suction disc on top of their heads. But the footage showed the fish abandoning the usual cling-on approach and instead vanishing directly into the rays’ rear ends. Sometimes, the remoras disappeared so deeply up their hosts’ back passage that only their tails could be seen poking out. In others, half the fish dangled from the cavity. Scientists logged thousands of surveys between 2010 and 2025, spotting seven cases of what they delicately called “cloacal diving” and one case of gill attachment. Thankfully for the manta rays, the behaviour appeared in fewer than 1% of observations. So why on earth are these fish going where absolutely no one invited them? Researchers have a few theories. One is that the remoras are ducking inside the rays to avoid predators - using the rays’ hole as a panic room. Another is that they’re feasting on parasites or organic matter lurking in the openings. There’s also a more practical explanation: by tucking themselves inside the manta ray, the remoras avoid the battering force of rushing seawater and save energy while travelling through the ocean. In other words, they may simply be taking the world’s weirdest budget flight. The manta rays, however, don’t appear especially thrilled about their uninvited passengers. In one video, a ray visibly shuddered after a remora wriggled inside. In others, rays flicked their huge pectoral fins in what scientists suspect was an effort to shake the freeloaders loose. The researchers added: “Although the exact mechanisms driving cloacal diving and gill attachment behaviors remain unclear, it is apparent that Echeneidae-host relationships are more physiologically and ecologically complex than previously understood.” Translation? Even scientists are still trying to work out why fish are apparently parking themselves inside manta ray bums.
Keywords: feature,oceans,manta rays,video,photo,fish,nature,bizarre,natural world
PersonInImage: Video of a Remora remora entering a Mobula yarae cloacal opening in Florida, USA.