Are sharks bottom feeders? This common question has a complex answer. While some sharks associate with the ocean floor, labeling all sharks as “bottom feeders” overlooks the diverse ways these marine animals obtain food.
What Makes an Animal a Bottom Feeder?
A “bottom feeder,” or benthivore, is an aquatic animal that primarily obtains food from the bottom of a body of water. They feed on organisms living on or within the seafloor, or on detritus that sinks to the bottom. Strategies include scavenging, grazing on plants or algae, or actively hunting other benthic creatures.
Many bottom feeders have specific physical adaptations for this lifestyle. Catfish, for example, often have downward-pointing mouths to scoop food. Flounders and other flatfish exhibit flattened bodies for blending with the seafloor. Crabs, sea cucumbers, and various worms also feed directly from the ocean bottom.
How Sharks Really Hunt and What They Eat
Most shark species are apex predators that hunt across various oceanic zones, including open water, near the surface, or in mid-depths. Their hunting methods range from high-speed pursuits to stealthy ambushes. Sharks employ senses like an acute sense of smell and the ability to detect electrical fields to locate prey.
Shark diets vary widely, reflecting their habitats and hunting techniques. Many species primarily consume fish, while larger sharks may target marine mammals like seals and sea lions. Some, like the massive whale shark, are filter feeders that consume plankton and small schooling fish by swimming with open mouths.
Sharks possess specialized teeth adapted to their diets. Great white sharks, for instance, have large, triangular teeth for tearing flesh from marine mammals. In contrast, sharks consuming hard-shelled prey have flatter, crushing teeth.
Specific Sharks That Feed Near the Ocean Floor
While many sharks are open-water predators, a distinct group feeds predominantly on or near the ocean floor. These sharks are often found in benthic environments, using specialized hunting techniques for seafloor prey. Their presence near the bottom does not classify them as detritivores like some other bottom feeders.
Nurse sharks are nocturnal bottom-dwelling sharks that rest on the seabed during the day. At night, they become active hunters, using powerful suction to feed on crustaceans like lobsters and crabs, mollusks, and small fish. They can pump water over their gills, remaining stationary on the bottom while breathing.
Angel sharks, with flattened, ray-like bodies, are ambush predators that camouflage by burying in sand or mud. They lie in wait for unsuspecting prey like bony fish, crustaceans, and cephalopods, launching a rapid, suction-driven attack. Their body shape and coloration allow them to blend seamlessly with the seafloor.
Wobbegong sharks, or carpet sharks, are ambush predators blending into the ocean floor with patterned skin and dermal lobes. They are primarily nocturnal, waiting for fish, crabs, and lobsters to come within striking distance before using strong jaws and suction. Horn sharks are slow-moving, nocturnal hunters that use powerful jaws and molar-like teeth to crush hard-shelled prey like mollusks and sea urchins.