Boat engine noise may therefore attract sharks to boats, particularly in cases where depredation on fishing lines has caused sharks to associate boat engine noise with the availability of hooked fish to consume (Mitchell et al., 2018a).

Sharks follow boats primarily due to sensory curiosity and the association with food, rather than predatory aggression. Boats create low-frequency vibrations and water pressure changes that sharks detect through their lateral lines, which are sensitive organs that perceive movement in the water. To a shark, these vibrations can mimic the sounds of a struggling fish or a concentrated school of prey. Additionally, many sharks have learned to associate boats—especially fishing vessels—with an easy meal; they follow the "chum slicks" (scent trails) or the sound of an engine "revving," knowing that discarded fish guts or a struggling catch might soon be available. Some species, like the Great White or the Tiger Shark, are also attracted to the electromagnetic fields generated by the boat's metal components and sacrificial anodes. In 2026, marine biologists emphasize that this "circling" behavior is often just an investigative "exploratory" phase where the shark is using its electroreceptors to identify the large, vibrating object in its territory, a behavior that is frequently misinterpreted by humans as a sign of an impending attack.