Megamouth Shark

Megamouth sharks are the smallest of the three filter feeders, discovered relatively recently in 1976. Since then, very few specimens have been caught or observed in the wild, leaving scientists struggling to learn more about it. Compared to the other two filter feeders – the whale and basking sharks – they look unique owing to their broad heads and rubbery lips.

Megamouth Shark

Megamouth Shark Scientific Classification

Kingdom Animalia
Phylum Chordata
Class Chondrichthyes
Order Lamniformes
Family Megachasmidae
Genus Megachasma
Scientific Name M. pelagios

Description

These are enormous sharks, with males being 13 ft long while females are a bit longer at 16 ft. According to reports, the average weight of a megamouth shark is 2,679 lb.

As their name indicates, these sharks have quite a wide mouth, capable of opening up to 4 ft, however, their snout is small and round and their teeth are tiny. There are 50 rows of teeth in the upper jaw and 75 in the lower one. They have a stout build with a flabby body which tapers off towards the posterior end – contributing to these sharks being poor swimmers. Their bulbous heads give them an appearance of a small orca. They have a set of pointed dorsal fins, the first being larger than the second, two pectoral fins that taper off, a tiny pelvic fin, and a spiny anal fin.

Megamouth sharks are darker dorsally, brownish-black, dark blue, or gray, while lighter ventrally. Notably, they have a silvery white band on their upper jaw that reflects light.

Where do they live

These sharks have been recorded in the Atlantic, Indian, and Pacific oceans. However, as the species is rare, the exact range remains unknown. Places where the megamouth has been spotted more than once include the Hawaiian Islands, Japan, the Philippines, and Taiwan.

The megamouths are deep-sea species that live at depths of 15000 ft. However, scientists believe they travel to the surface to feed at night.

Behavior

Dietary

They are omnivorous, with a diet consisting of plankton, shrimp, krill, and jellyfish.

Predatory

Megamouths are filter feeders that use ram feeding to capture their prey. They open their mouths and sift through the water, looking for food. The tiny organisms they feed on get stuck on their teeth and papillose gill rakers, with the water they swallow getting expelled through the gills.

Migratory

These sharks follow a diel cycle, staying in deep waters during the day and coming to the shallows at night to feed.

Reproductive

Besides the fact that these sharks give live birth, little is known about the reproductive behavior of the megamouth. Experts assume that they mate year-round, and the lack of genetic diversity among captured specimens from around the world indicates that the entire species might form a single interbreeding population.

Megamouth Shark Image

Adaptations

As feeding underwater is difficult, especially for a shark as giant as the megamouth, over time, they have developed wider mouths to take in more water to capture more significant quantities of food. The white band on their upper lip also reflects light luring their prey towards them.

Their huge liver lets them produce liver oil in greater quantities to lower specific gravity and increase hydrostatic support, allowing them to float more easily.

Interactions with humans

As per the IUCN, these sharks are categorized as “Least Concern” or “LC”. Humans pose a low threat to the megamouth from fishing and other activities. Any natural predators they have, like sperm whales and cookiecutter sharks, will not cause any significant population decline.

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