What do whale sharks eat?

Whale Shark Feeding Habits

Despite being the largest fish in the ocean, whale sharks (Rhincodon typus) feed on some of the smallest organisms in the sea. They are filter feeders — like baleen whales — straining tiny prey from the water rather than hunting large animals. It is important to note that whale sharks are actually sharks, not whales.

Primary Diet

Whale sharks feed on a variety of small organisms:

• Plankton: Microscopic floating organisms, both plant (phytoplankton) and animal (zooplankton), form a major part of their diet
• Krill: Small shrimp-like crustaceans, similar to what blue whales eat
• Fish eggs: Whale sharks are known to congregate at mass fish spawning events to feed on clouds of eggs
• Small fish: Anchovies, sardines, mackerel, and small tuna are consumed when available
• Squid: Small squid and other cephalopods

How Whale Sharks Feed

Whale sharks use several feeding techniques:

Ram filter feeding: The whale shark swims forward with its enormous mouth open — up to 5 feet (1.5 meters) wide — and water flows through its gills. Specialized filter pads in the gill arches trap food particles while allowing water to pass through.

Active suction feeding: Whale sharks can also station themselves vertically in the water and bob up and down, actively sucking water and prey into their mouths. This behavior is often observed when they feed on concentrated patches of fish eggs or plankton.

Cross-flow filtration: Research has shown that whale sharks use a mechanism similar to industrial cross-flow filtration, where particles are concentrated at the back of the throat rather than clogging the filter pads. This allows them to feed continuously without stopping to clear their filters.

How Much Do Whale Sharks Eat?

A whale shark can filter over 1,500 gallons (6,000 liters) of water per hour while feeding. Despite their massive size — up to 40 feet or more — their actual food intake is modest compared to large baleen whales. Scientists estimate that whale sharks consume roughly 46 pounds (21 kg) of plankton per day.

Teeth — But Not for Eating

Whale sharks have over 300 rows of tiny teeth (each tooth is only about 6 mm long), but these teeth play no role in feeding. Scientists believe the teeth may be vestigial remnants from ancestral sharks that were active predators. The filter pads in their gills do all the work of capturing food.

Where Whale Sharks Feed

Whale sharks are found in warm tropical and temperate waters worldwide. They are known to aggregate at specific locations where food is abundant:

• Ningaloo Reef, Australia: Coral spawning events attract large numbers of whale sharks
• Isla Holbox, Mexico: Plankton-rich waters draw seasonal gatherings
• Oslob, Philippines: Year-round populations near coastal areas
• Djibouti: Gulf of Tadjoura hosts feeding aggregations

These feeding aggregations make whale sharks popular targets for ecotourism, particularly snorkeling and diving experiences. Because they feed on tiny prey and are not dangerous to humans, whale sharks are considered gentle giants of the ocean.