Remora (Echeneis naucrates)

FishMarineHitchhiker

Overview

Remoras (family Echeneidae), often called sharksuckers, are slender marine fish with an extraordinary adaptation: a flat, oval, ridged suction pad on top of the head — actually a modified dorsal fin — that works like a powerful sucker. With it, a remora can attach itself firmly to a much larger animal and ride along, hitchhiking across the ocean. The live sharksucker (Echeneis naucrates), shown here, is a common example.

By latching onto sharks, rays, sea turtles, whales, and even boats and divers, remoras get free transport, protection, and easy meals — without having to swim constantly themselves.

Note: there are several remora species; details here use the live sharksucker as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Remoras live in warm tropical and subtropical oceans worldwide, in open water and around reefs — usually wherever their large host animals are found. Because they travel attached to wide-ranging hosts such as sharks and turtles, individual remoras can cover great distances across the sea.

Diet

Remoras have a flexible, opportunistic diet centred on their hosts. They feed on scraps from the host's meals, on its external parasites (such as copepods), and on its sloughed skin and faeces, and they also catch small free-swimming prey and plankton. This mix of cleaning and scavenging is part of why hosts often tolerate them.

Behavior

The remora's suction disc has rows of movable, slat-like ridges that it can raise to create suction and grip a host's skin tightly, yet it can release and reposition easily; the faster the host swims, the firmer the hold becomes. The relationship is generally seen as commensal — the remora benefits from transport, shelter, and food, while the host is largely unaffected and may even gain from having parasites removed. Remoras can also detach and swim freely, and some aggregate around feeding sharks. Their hitchhiking lifestyle saves them the energy of constant swimming.

Human Interaction & Conservation

Remoras are familiar to divers and snorkelers, sometimes attaching to people or boats, and they feature in the folklore and traditional fishing of some cultures (where tethered remoras were reportedly used to help catch turtles). They are harmless to humans and are not of major conservation concern, though they depend on healthy populations of their host animals. Consult authoritative sources for details.

More photos of the remora