The basking shark, a colossal marine creature, often sparks curiosity regarding its potential danger to humans. Despite its imposing size, the answer is clear: basking sharks do not eat humans. These gentle giants pose no predatory threat to people, a fact supported by their unique feeding habits and docile nature. Understanding their biology and behavior reveals why they are harmless.
What Basking Sharks Eat
Basking sharks are filter feeders, meaning they strain microscopic organisms from the water as they swim. Their diet consists primarily of zooplankton, which includes tiny crustaceans like copepods, fish eggs, and invertebrate larvae. They are one of only three known plankton-eating shark species, alongside the whale shark and megamouth shark.
To feed, a basking shark swims with its enormous mouth wide open. This process, known as passive ram filtration, allows water to flow through specialized gill rakers that act like sieves. These bristle-like structures, which can be covered in mucus, trap the tiny prey while water passes over the gills and is expelled. Their teeth are numerous but very small, typically 5-6 millimeters and hooked, serving no purpose in capturing large prey.
Basking Shark Behavior and Size
Basking sharks are known for their calm and slow-moving disposition. They are the second-largest living fish, reaching lengths of around 7.9 meters (26 feet) and weighing about 4.65 metric tons (5.13 short tons). Despite their immense size, which can be comparable to a double-decker bus, they are not aggressive.
Their common name, “basking shark,” comes from their habit of feeding near the surface, with their dorsal fins often visible. They often cruise leisurely, sometimes in pairs or large groups, and are even capable of breaching, or leaping clear out of the water. This behavior is thought to be related to mating or dislodging parasites.
Are Basking Sharks Dangerous to Humans?
Basking sharks are considered harmless to humans. There are no verified records of basking sharks attacking or consuming people. Their specialized feeding mechanism, designed for microscopic organisms, means that humans are not part of their diet.
While basking sharks pose no predatory threat, their large size can lead to extremely rare, accidental interactions. For instance, a historical report from 1937 describes a breaching basking shark accidentally capsizing a boat. Additionally, their skin is covered in placoid scales, which are tooth-like structures that make their skin very rough, similar to sandpaper. Contact with their skin could cause cuts or scrapes, but this is not a predatory action. If encountered, basking sharks tend to be tolerant of divers and boats, and they often avoid larger objects, including swimmers.