### Identification The Megamouth Shark (*Megachasma pelagios*) is an ethereal, tadpole-shaped giant that reaches lengths of up to 18 feet (5.5 meters). Its most striking feature is its disproportionately massive, bulbous head and cavernous mouth, which stretches past its small, black eyes. Unlike the streamlined Great White, the Megamouth has a soft, flabby body and asymmetrical tail. It is charcoal-grey to brownish-black dorsally and creamy-white below. Look specifically for the silvery-white "mustache"—a reflective band on the upper jaw that distinguishes it from the Basking Shark (which has a pointed snout) and the Whale Shark (which is covered in white spots).
### Habitat & Range This is a true deep-sea wanderer of the open ocean (pelagic). It is found globally in tropical and warm-temperate waters, including the Pacific, Atlantic, and Indian Oceans. It occupies the mesopelagic zone, often descending to depths of 500 feet during the day and rising toward the surface at night.
### Behaviour A sluggish, solitary swimmer, the Megamouth is best known for its diel vertical migration. It follows the "deep scattering layer" of plankton, spending its days in the dark abyss and ascending to the epipelagic zone at dusk. In the field, an observer would notice its slow, rhythmic swimming style—it is built for endurance and energy conservation rather than speed.
### Diet The Megamouth is one of only three plankton-eating shark species. It is a suction-filter feeder, swimming with its massive mouth agape to engulf swarms of euphausiid krill, copepods, and small jellyfish. It uses its internal gill rakers to strain these tiny organisms from the seawater.
### Fascinating Fact The Megamouth remained entirely unknown to science until 1976, when the first specimen was accidentally hauled up after becoming entangled in the sea anchor of a U.S. Navy ship off the coast of Hawaii! To this day, fewer than 100 confirmed sightings have ever been recorded.