When scientists first discovered the megamouth shark in 1976 off the coast of Hawaii, it struck them as so bizarre that, to classify it, they created an entirely new genus and family.
Today, little is still known about the shark save for the fact that it has a large gaping mouth, which is indeed, very mega.
While swimming off the coast of Indonesia's Komodo Island, one diver got a lucky sighting of one of these rarely seen sharks.
The diver was exploring the northernmost string of the islands known as Gili Lawa Laut, a popular diving spot for tourists when the shark happened to swim by. Video shows a clear image of the shark gently gliding through the water. It's characteristic head and mouth get within close proximity of the diver before it turns and swims away.
Extremely rare megamouth shark filmed
The Florida Museum of Natural History keeps an official list of megamouth shark sightings dating back to its discovery in 1976. In the past 41 years, just over 60 sightings have been confirmed. The International Union for the Conservation of Nature (IUCN), which keeps active records of world species populations, notes that 102 specimens have been observed.
While the species is mysterious, megamouth sharks present little threat to people. The sharks are filter feeders and have what the Florida museum characterises as, "a soft, flabby body and poor swimming skills." The big fish are believed to grow roughly 17 feet long. In addition to their wide-stretched mouths, the sharks can also be recognised from their snout-shaped heads. (Watch a tiny blue shark dominate the ocean's fastest shark.)
The sharks have been found in shallow waters near the water's surface and ocean depths of up to a mile, suggesting the animals are diurnal, and regularly alternate between deep and shallow.
They've been spotted primarily near Japan and Taiwan, but sightings have occurred in the Atlantic, Pacific, and Indian Oceans. Because of its wide range of distribution, the IUCN lists the megamouth shark as an animal of "least concern."
Beachgoers rescue shark from fishing line
Megamouths, however, aren't quite out of the water. The organisation notes that more incidences of capture have been reported by fisheries, particularly in southeast Asia. Bycatch is thought to be the biggest threat facing megamouth sharks and an issue the nature conservation group suggests could threaten the shark's existence if not closely monitored.
Most recently a megamouth shark was caught off the coast of Japan where it was mistakenly reeled into a fishing boat as bycatch. The shark was promptly released and later found dead on the ocean floor from what scientists believe could be stress-related health issues.