The “Megamouth” shark, a rare and substantial species, can reach weights of up to 2700 pounds (1215 kg). Despite its size, it is the smallest among the three filter-feeding shark species, trailing behind the whale shark and the basking shark.
Characterized by its remarkably large, circular mouth, the Megamouth shark features a brownish-blackish color on top and white underneath, along with a broad, rounded snout and distinctively large head adorned with rubbery lips.
Measuring up to 18 feet in length, this shark was first discovered in California, Japan, and Australia, including the Hawaiian islands. Its habitat and distribution remain uncertain, but a few sightings have been recorded in areas of the Pacific, Indian, and Atlantic Oceans, including countries such as Brazil, Senegal, the Philippines, and Indonesia.
The Megamouth shark is recognized for its prominent mouth, which it employs to filter plankton from the water. It is believed that its lips are bioluminescent, attracting prey in the deep sea where it typically resides.
Due to the disparity in size between its mouth and jaw compared to its abdomen, the Megamouth lacks strong swimming abilities. It is thought to use bioluminescent strips along its upper jaw to lure prey and then engulf it in a single motion, similar to the feeding mechanism of a whale.
This behavior is attributed to the shark’s restricted internal gill openings and jaw morphology. Scientists have used radio tags to track the shark’s vertical migration pattern, revealing that it undergoes shifts in depth over a 24-hour period.
Mating through internal fertilization, Megamouth sharks give birth to a small number of relatively large offspring. However, they do not connect to their young through a placenta. Instead, during the gestation period, the mother likely provides her young with unfertilized eggs that they actively consume for nourishment.
After birth, young Megamouth sharks quickly become filter feeders. Although not directly targeted by commercial fishermen, these sharks are sometimes sold when accidentally captured in fisheries that are aiming for other species.
References: Wikipedia, Smithsonian Magazine, Australian Museum, Wildlife Online, Oceana, Mental Floss, Fox News
Image sources: Wikipedia, NDTVA, Smithsonian Magazine, Australian Museum, Wildlife Online, Taiwan English News, TurboSquid, Mental Floss, Taiwan News, NextStepTV