The basking shark, a colossal marine creature, is the second-largest fish in the world. Despite its immense size, often reaching 12 meters (approximately 40 feet), it is known for its gentle nature. Unlike many of its shark relatives, the basking shark is not a predator. It navigates the ocean with a calm demeanor.
The Basking Shark’s Primary Diet
The basking shark’s diet consists almost exclusively of zooplankton, tiny marine organisms that drift with ocean currents. This includes small crustaceans like copepods, barnacle larvae, and fish eggs. Despite its massive body, the basking shark sustains itself entirely on these microscopic organisms.
To acquire sufficient nutrition from such small prey, these sharks must process an enormous volume of water. A single basking shark can filter up to 1,814 metric tons (approximately 4 million pounds) of water per hour. This capacity allows them to gather the vast quantities of zooplankton needed to support their immense size. Basking sharks exhibit seasonal migrations, often following zooplankton blooms to ensure a continuous food supply.
How Basking Sharks Feed
The basking shark employs a unique filter-feeding mechanism to capture its food. It swims slowly with its enormous mouth wide open, allowing water to flow continuously through. This method, known as passive ram filtration, relies on the shark’s forward movement to push water into its mouth.
As water passes through the shark’s mouth, specialized structures called gill rakers, which resemble combs, filter out tiny food particles. These bristly, dark structures trap zooplankton while allowing filtered water to exit through the gill slits. The basking shark occasionally closes its mouth to swallow the accumulated plankton.
A Unique Feeding Strategy Among Sharks
The basking shark’s filter-feeding method sets it apart from most other shark species, which are typically active predators. Unlike sharks like great whites or tiger sharks, it does not pursue or bite large prey. Its specialized diet and feeding approach render it harmless to humans.
As a filter feeder, it plays a part in regulating plankton populations, contributing to the balance of marine ecosystems. By consuming vast quantities of plankton, basking sharks help cycle nutrients within the ocean, supporting overall water quality and the health of the marine environment.