Megamouth Shark Facts

The megamouth shark is so rarely seen and so unusual that every sighting has been recorded in the scientific community. Scientifically known as Megachasmapelagios, the megamouth shark was only recently discovered in 1976.

The scientific name is made up of Greek words meaning “great,” “cave,” and “of the sea.” In fact, the entire translation of the name is “huge yawning cavern of the open sea.” The megamouth shark’s nickname is “alien of the sea.”

Due to its more recent discovery and lack of sightings, a lot of facts are yet to be known about the megamouth shark. Megamouth is considered to be less active than most sharks and possibly even a poor swimmer. It is believed to be harmless to humans.

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Scientists are still gathering data about the distribution of the megamouth. Sightings have been confirmed in the Atlantic, Pacific, and Indian Oceans, and this species is believed to be wide-ranging. Scientists have discovered megamouth sharks spend the day in the deep depths of the ocean but return to more shallow depths at night. This behavior is called “vertical migration.”


Megamouth sharks can grow to reach 17 feet or greater, and the heaviest recorded weight was around 2,000 pounds!

Megamouth sharks are dark grayish brown on their dorsal side with ventral colors of light gray to white. Both male and female megamouth sharks have white bands on their snouts, which scientists believe could be a recognition tool between individuals of the species.


The megamouth shark’s anatomy is very interesting since it is so different than other species of sharks. It has a soft body and fins, an unequal tail, and an overall weak body. Interestingly enough, the slow megamouth shark belongs to the same family as the fastest shark ~ the shortfin mako shark!

As its common name hints, the megamouth shark has an oversized mouth. Its head is also large enough to look out of proportion to its body. However, a huge mouth does not mean huge teeth. Megamouth sharks have very small teeth and a lot of them! They have about 50 rows of teeth, but only 3 rows are considered functional or useful.


Despite its size, the megamouth shark is not to be feared by humans. It joins the basking shark and the whale shark as one of three filter feeders in the shark family. Megamouth shark puts its giant mouth to use by holding it open wide and ingesting, or swallowing, krill and plankton along with water. After gathering enough prey, the mouth will then close, and a special filtering process enables the megamouth shark to expel or force out the water using its gills. Scientists have not yet been able to study a live specimen or example of its species to confirm their thoughts about the feeding process.

Special Adaptations

Besides its large size, the megamouth shark possesses more interesting features. Its upper jaw has two sheets of silvery tissue. Scientists have no clue what this reflective tissue might be used for!


Like many other areas of megamouth sharks, little is known about the reproductive process of megamouth sharks. They are believed to be ovoviviparous, with the babies, called pups, starting life out as an egg, being hatched inside the mother, and then being born live. There is no information currently available about the size of litter or how long pups are carried by females.

Conservation Status

The megamouth shark is believed to be a wide-ranging shark, although it is not often seen. However, in recent years, it has become increasingly taken as bycatch by commercial fishermen. Because of these reasons, it is currently listed as a species of Least Concern.

Megamouth sharks are probably encountered on a more frequent basis than believed but may not be reported. Scientists have been able to tag megamouth sharks and are hopeful more information will be gathered in the near future.

Fact Attack

  • Many specimens of megamouth sharks have been found washed up on the beaches!
  • There are some scientists who believe the lower jaw of megamouth may exhibit bioluminescence, or the production of light by living things, such as fireflies, to attract prey. There has been no proof backing up this thought, but scientists are still studying the possibility.

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