The whale shark, the largest fish in the ocean, is recognized by its immense size and distinctive spotted patterns. These creatures can reach lengths exceeding 40 feet. Despite their impressive size, whale sharks are known for their gentle nature, posing no threat to humans. They navigate tropical and warm waters across the globe.
The Truth About Whale Shark Teeth
Whale sharks possess teeth, a fact that often surprises many. These teeth are exceptionally tiny, measuring only a few millimeters in length, and are pointed backward within their mouths. An adult whale shark can have up to 300 rows, totaling around 3,000 to over 15,000 teeth. These small teeth are considered vestigial structures, meaning they have lost their original function. Composed of dentine and covered in a thin layer of enamel, they play no direct role in biting, chewing, or capturing food.
How Whale Sharks Feed
Whale sharks employ a unique filter-feeding mechanism to obtain sustenance. They open their broad mouths, which can stretch up to 4 feet wide, to engulf vast quantities of water. Specialized structures called gill rakers, located within their gill slits, act as a sieve. These filter pads effectively strain small food particles from the water while allowing filtered water to pass out through the gills. This process involves cross-flow filtration, where water flows parallel to the filter pads, directing denser food particles towards the throat.
Whale sharks can actively suck in water, especially when prey concentrations are high, sometimes adopting a stationary, vertical position. They also engage in ram filter feeding, swimming forward with their mouths open. The shark closes its mouth to swallow concentrated food and has been observed “coughing” to clear its filter pads of accumulated particles.
What Whale Sharks Eat
The diet of whale sharks consists primarily of very small organisms, consistent with their filter-feeding strategy. Their main food source is plankton, encompassing both zooplankton (like copepods, krill, and various fish larvae) and phytoplankton. They also consume small nektonic life, including jellyfish, fish eggs, and small schooling fish such as sardines, anchovies, and mackerel.
Whale sharks are considered opportunistic feeders, consuming whatever suitable prey is available in the waters they filter. Their narrow throats, often compared in size to a quarter, limit the dimensions of the prey they can swallow. While their diet is predominantly small marine organisms, they have also been noted to ingest and partially digest Sargassum, suggesting an omnivorous component to their feeding habits.