Most scientists classify the relationship between the shark and the remora as a commensalit relationship, because the remora benefits from the transportation and food that the shark provides, while the shark does not seem to be harmed. However, there are some scientists who believe that the remora are irritating to sharks, and others who believe the relationship is symbiotic.
Remoras latch onto sharks and other fish for two reasons. One reason is because they need a steady flow of moving air so that they can breathe. Scientists have observed that remoras cannot survive in tanks with stagnant water. Hitching onto larger, faster moving animals such as sharks allows remoras to move faster than they could just by swimming.
The other reason why remoras attach to larger fish is so that their hosts can serve as food source. Some scientists even view the remora as a symbiotic fish because it can eat small parasites on the shark's body as well as scraps that the shark gives off.
However, some scientists maintain that remoras are parasitic because they are bothersome to sharks. They move about a lot on the shark's body and may attach themselves to areas that are sensitive or interfere with the shark's natural hydrodynamics. These scientists claim that sharks will perform maneuvers and even jump from the water to shake off remoras. There is no evidence that remoras have ever been eaten by a shark, as they have never been found in a shark's stomach.