The megamouth shark (Megachasma pelagios) is a rare and enigmatic species inhabiting the ocean’s depths. Discovered in 1976, it remains one of the least understood sharks on Earth.
This filter-feeding shark is characterized by its massive mouth, which it uses to capture plankton and small organisms. Its slow movements and vertical migrations through the water column suggest adaptations to its deep-sea environment. Bioluminescent photophores lining its mouth may play a role in attracting prey.
Despite its impressive size, the megamouth shark is harmless to humans. Studying this elusive creature provides valuable insights into the diversity and adaptations of marine life, highlighting the vast mysteries still hidden within our oceans.
Appearance
Megamouth sharks have stout bodies and bulbous heads. Their mouths, for which they’re named, are broad and extend behind their eyes. They’re incredibly easy to recognize, part of the reason why they have captured the public’s imagination.
They have soft bodies with large oily livers, flabby muscles and skeletons that are poorly calcified. These features help them to swim very slowly without sinking. They have two pointed dorsal fins, two tapering pectoral fins, a relatively small pelvic fin, and a small, pointed anal fin.
Megamouth sharks have up to 50 rows of teeth in their upper-jaw and up to 75 rows of teeth in their lower-jaw. Their mouths can reach up to 1.3 m or 4 ft 3 inches in width.
They are blackish-brown in color, with paler sections on their undersides around between their eyes. The studied specimens have silver membranes on the roof of their mouths and a purplish-brown tongue. It’s thought that a white band around the snout is used to attract prey or maybe a way of recognizing individuals.
It was initially thought that this light-colored band might be phosphorescent. But, that has since been proven untrue. It is only highly reflective. Recorded specimens have reached a maximum size of around 17 feet or 550 centimeters. It’s been reported that sharks can weigh up to 1,215 kg or 2,679 lb.
Did you know…
The megamouth is quite different in appearance from other sharks, so much so that, as noted above, some scientists believe that it’s part of its own family, Megachasmidae. Or that it might be a part of the Cetorhinidae (basking shark) Lamnidae (mako, white, and porbeagle sharks) and Alopiidae (thresher sharks). It is thought to be the most primitive living species within the order Lamniformes, which contains all the aforementioned families.
Habitat
The megamouth shark lives in tropical and temperate waters worldwide in shallow coastal and open-water pelagic waters from the surface to deeper depths of 1,500 meters (about 4,920 feet). They are found in the Atlantic, Indian, and Pacific oceans.
Sharks have been found in different oceans, from northern Japan to southern California and as far south as Hawaii, and up to depths of 1,000 meters or 3,280 feet. The majority of sharks captured or discovered have been in Japan and the Philippines. The Philippines is one of the most important habitats for the megamouth shark, ranking
number two globally, next to Taiwan
Diet
It’s unclear exactly how megamouth sharks feed. Scientists have had few opportunities to study this behavior. However, they believe the sharks swim slowly after their prey and use their large mouths to trap prey inside. The mouth closes, and with the jaw retracted, the prey can’t escape.
They have a bright white band on their upper jaw that is only visible when the mouth is open.
Megamouth sharks are filter-feeding sharks, They will eat anything from shrimp to jellyfish, krill, copepods, and more. Scientists believe that euphausiids are their primary food source.
Reproduction
Like their feeding habits, more information is needed to fully understand the megamouth’s reproduction. Males mature at 4.26 meters and females at 5.12 meters in length. They are thought to mate around the fall. There may be some evidence that the mating process can turn violent.
It’s believed these sharks are ovoviviparous. This means that the sharks develop in eggs within the mother’s body and remain there until they hatch. During the gestation period, the mother likely provides her young with unfertilized eggs that they actively eat for nourishment.
Threats
The IUCN lists them as “least concern,” suggesting that they are not commonly affected by humanity’s intrusion on the ocean, climate change, or fishing practices.
Since being first reported in 1976, there have been a total of 294 known records.
Their natural predators include sperm whales and other larger whales. Florida Museum also notes that they may be attacked by the cookie-cutter shark, a small shark that attaches and removes small pieces of flesh. It’s a parasitic shark, evidence of which has been seen on all megamouth specimens.
6 More Astonishing Facts About the Megamouth Shark
- Photophores lining its mouth emit a bioluminescent glow, possibly attracting plankton and small prey.
- Females usually have fewer teeth rows than males.
- It may belong to its own family, separate from all living sharks.
- They swim with their mouths open to capture fish and other prey.
- Their mouths extend behind their eyes.
- Megamouths undertake vertical migrations, traveling from depths of 1500 meters during the day to near the surface at night.
- Their scientific name is Greek origin, meaning, the giant yawner of the open sea.
FAQs
Is the megamouth shark still alive?
While it is rarely seen by humans, the megamouth shark is still alive. For recorded history, the shark has been spotted 294 times until recently (Although scientists believe that there are more unrecorded instances).
How old do megamouth sharks get?
It’s unclear how old megamouth sharks get due to the general lack of information about their lives. But, if they are similar to other sharks, they live between twenty and thirty years.
Is megamouth shark aggressive?
Megamouth sharks are not aggressive towards humans. As filter feeders, they lack the predatory instincts and teeth of aggressive shark species. Their slow movements and lack of documented encounters with humans further suggest a docile nature.
Why is the megamouth shark so rare?
The megamouth shark’s rarity is attributed to its deep-sea habitat and elusive behavior. Inhabiting the vast and remote depths of the open ocean, they undertake vertical migrations that further reduce the likelihood of human encounters. As filter feeders with slow movements, they may not be readily attracted to fishing activities.
