This week’s shark is strange and mysterious. The Megamouth Shark (Megachasma pelagios), as you can guess, has a bulbous head and large mouth that contains many rows of small hooked teeth. Since the discovery of the Megamouth in 1976, there have been many hypotheses about its evolutionary background based on its feeding apparatuses and other physical features. Its unique features lead to the description of a new family, genus, and species was formed.
Some light has been shone on this little-studied shark. In 1990 a Megamouth Shark was tagged and tracked near Dana Point, California. The tracking data from this shark showed that it dove deep during the day and returned to the surface at night. This pattern of diving and surfacing is known as vertical migration. Many animals including squid, krill, and other zooplankton also exhibit vertical migration. Megamouths feed primarily on krill, so it is believed that they migrate to follow their prey.
Does such a large shark have any predators? While rarely seen, there is some evidence that they are preyed upon by sperm whales, which leave visible scars. Megamouths are also food for parasites including the Cookiecutter Shark (Isistius brasiliensis), which also leaves bite marks and scars. Click here to read more about Cookiecutter Sharks. Megamouths also host internal parasites including cestode and typanorhynch worms.
Join us nest week to read about the final shark of the year!