A remora, or suckerfish, is a unique creature found in marine environments. This fish, recognizable for its long, slim bodyline, is most often found attached to larger marine creatures, such as sharks and manta rays. Using a unique sucking organ, remoras can travel for miles attached to a larger host, picking up meals along the way.
There are several different species of remora, most living in tropical or sub-tropical waters. They have been found in more temperate waters, presumably arriving there via the migration of the remora's host animal. There are at least eight known species of the remarkable remora, ranging from the tiny Remoropsis pallidus to the 3 foot (91.44 cm) sharksucker.
Remoras attach to a host via a sucker-like organ on the dorsal fin. This oval disc features slats that allow suction to occur, allowing the remora to latch on by swimming backward to lock the slats down. A remora can detach at any time simply by swimming forward. Although remoras swim quite well, the fish greatly benefits from this easy form of travel as it requires little energy expenditure. In the difficult world of the deep, sometimes the way to survive is by expending the least energy to get the most food.
There is some scientific debate about what remoras eat while riding their larger hosts. While some believe they scavenge for scraps from the host creature's meals, others believe they devour parasites and surface crustaceans that live on the host's skin. Some scientists also believe that remoras increase their symbiotic relationship with a host by living on the host's feces.
Certain species of remora can be quite picky about their host animals. The large sharksucker prefers attaching to sharks, while one Australian species attaches almost exclusively to whales. Other common hosts include dugongs, rays, and turtles. Smaller species may attach to large fish, such as tuna, marlin, and swordfish. Since the hosts seem to tolerate the remoras, it is believed that the suction does not cause discomfort and that the fish may even be beneficial to their hosts by eating parasites.
Remoras may provide unexpected rides themselves, particularly those attached to large rays. In tropical waters where giant manta rays flourish, free divers often take advantage of the remora-ray relationship in order to take a ride themselves. By grabbing onto conveniently attached remoras, divers can go “ray riding,” using the remoras as handlebars to stay attached to the graceful ray.