Sharks are often imagined as formidable ocean hunters. While many species are indeed apex predators, their feeding behaviors encompass a surprisingly broad spectrum, extending far beyond active hunting to include specialized and unexpected diets.
The Majority: Apex Predators
Many shark species are apex predators, preying on a variety of marine animals. They possess adaptations like powerful jaws, sharp teeth, and keen senses to locate and capture their meals. Their diets can be quite diverse, often including bony fishes, marine mammals, and even other sharks.
Great white sharks are well-known for their predatory prowess, with adults primarily targeting seals, sea lions, porpoises, dolphins, and small whales. They often employ ambush tactics, stalking prey from below before launching a sudden, powerful strike. This initial attack is designed to inflict a massive, fatal bite, after which the shark may retreat and wait for the prey to succumb.
Tiger sharks are opportunistic and versatile predators, sometimes called “garbage cans of the sea” due to their wide-ranging diet. Their prey includes fish, crustaceans, seabirds, marine mammals, and sea turtles. These sharks often hunt closer to shore at night, using stealth and camouflage. Mako sharks, among the fastest, primarily feed on bony fishes like herring, mackerel, swordfish, and squid, but also consume other sharks and small marine mammals.
The Exceptions: Filter Feeders
Not all sharks are active hunters; some of the largest species are filter feeders, consuming microscopic organisms from the water. These sharks possess specialized structures that allow them to strain tiny food particles. The three primary species in this group are the whale shark, the basking shark, and the megamouth shark.
Whale sharks, the largest fish in the ocean, are filter feeders that primarily consume plankton, including copepods, krill, and small fish larvae. They feed by swimming with their enormous mouths open, allowing water to flow through and trapping food particles with their gill rakers. They can also use a suction feeding method, drawing in large gulps of water to capture concentrations of plankton.
Basking sharks are the second-largest fish and filter feeders, primarily feeding on zooplankton, especially copepods. They employ a passive feeding strategy known as ram filtration, swimming slowly with mouths wide open to push water through their gill rakers, which then trap small organisms. Megamouth sharks, a more elusive species, also filter feed on krill, jellies, and other plankton, often performing daily vertical migrations.
Beyond Predation: Other Feeding Habits
Beyond predatory and filter-feeding behaviors, other shark species exhibit diverse and specialized feeding strategies. Some are primarily scavengers, consuming dead or decaying animals. The Greenland shark is known for opportunistic scavenging, feeding on carrion that can include fish, seals, and even terrestrial animal remains. These sharks are slow-moving but have an acute sense of smell, allowing them to locate carcasses in their cold, deep habitats.
Other sharks have diets highly specialized for benthic (bottom-dwelling) organisms. Horn sharks are nocturnal bottom dwellers that feed mainly on hard-shelled mollusks, echinoderms like sea urchins, and crustaceans. They possess uniquely adapted teeth: pointed front teeth for grasping and flat, molar-like back teeth for crushing hard shells. These sharks can generate a high bite force relative to their size to crack open their armored meals. This variety in feeding demonstrates the extensive range of adaptations within the shark family, extending far beyond the typical image of a swift hunter.