The megamouth shark is an enigmatic creature of the deep ocean, rarely encountered by humans. Its mysterious nature has long captivated scientists and the public, sparking curiosity about its biology. This article explores its dietary preferences and the specialized methods it employs to obtain food in its vast, dimly lit habitat.
Understanding the Megamouth Shark
The megamouth shark (Megachasma pelagios) is a large, deepwater shark with a distinctive appearance. It has a stout body, a broad, bulbous head with rubbery lips, and an immense mouth up to 1.3 meters (4 feet) across. These sharks typically range from 4 to 5.5 meters (13 to 18 feet) in length, making them the smallest of the three known filter-feeding shark species. The species remained undiscovered until 1976, when the first specimen was found off the coast of Hawaii. Since then, fewer than 300 specimens have been observed or caught, solidifying its status as one of the least understood sharks in the world.
Their Primary Food Sources
The megamouth shark is a filter feeder, consuming tiny organisms. Its diet primarily consists of zooplankton, small animals that drift in ocean currents. Key components include krill (euphausiid shrimp) and copepods. Their stomachs have also contained jellyfish, shrimp larvae, squat lobsters, and crab larvae.
These sharks exhibit diel vertical migration, ascending to shallower waters (0-50 meters) at night. During the day, they descend to deeper areas (700-850 meters), following the migratory patterns of their planktonic food sources.
The Unique Feeding Mechanism
The megamouth shark employs a specialized feeding strategy, swimming slowly with its enormous mouth continuously open to engulf water containing plankton. This “ram feeding” allows water to flow into its buccal cavity, where the food is then filtered. Inside its large gill slits, the shark has specialized, finger-like gill rakers composed of spongy tissue that effectively trap small organisms while allowing water to pass through.
Unlike some other filter feeders, the megamouth shark’s weak jaw muscles and soft fins suggest it may not rely on high-speed swimming to capture prey. Researchers hypothesize that it might use an “engulfment feeding” method, similar to humpback whales, where it takes in a large volume of water and then slowly filters out the food. A notable feature is a white band on its upper jaw, which becomes visible when its mouth is open and is thought to act as a lure, attracting plankton in the deep, dark ocean environment.