Manta ray
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? Manta
Ray Conservation status: Data
deficient
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 Giant Pacific Manta. A large symbiotic
suckerfish is visible on the manta's ventral
side
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| Manta
birostris Dondorff, 1798 |
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The manta ray, or giant manta, is the largest of the rays, ranging up to 6.7 meters (22 ft) across its pectoral fins (or "wings") and weighing up to 1,350 kg (3,000 lb). It ranges throughout the tropical seas of the world, typically around coral reefs. Mantas are most commonly black above and white below, but some are blue on their backs. A giant manta's eyes are located at the base of the cephalic fins on each side of the head, and unlike other rays the mouth is found at the anterior edge of its head. To breathe, the manta has like other rays five pair of gills on the underside. With distinctive "horns" on either side of its broad head, the manta is a prized sighting by divers. These unique horns are actually structures made by the pectoral fins where a part breaks off during the embryological stage and moves foreward and surrounds the mouth, which makes them the only known example where jawed vertebrates have evolved novel limbs (the so-called six-footed tortoise (Manouria emys) has of course not actually six legs, only enlarged tuberculate scales present on their thighs that looks a bit like an extra pair of hind limbs). These flexible horns are also called cephalic fins and are used to direct plankton and water into their very broad and wide mouth. To make them more streamlined when swimming, they are able to curl them up.
They evolved from bottom feeders a long time ago, but later adapted to become filter feeders in the open ocean. Because of their pelagic lifestyle as plankton feeders, some characterstics have been degenerated. All that is left of their oral teeth is a small band of vestigial teeth on the lower jaw, almost hidden by the skin. They are closely related to stingrays, but they don't have any stinger. Also their dermal denticals are greatly reduced in number and size, but are still present, and they have a much thicker body mucus coating than other rays. Their spiracles have become small and non-functional, all the water is taken in through their mouth instead.
To better swim throgh the ocean, they have evolved a diamond shaped body plan, using their pectoral fins as graceful "wings".
Mantas generally eat plankton, fish larvae and small organisms that are filtered out from the water by their gill rakers, a type of filter feeding that is called ram-jet feeding.
Taxonomically, the situation of the mantas is still under investigation. Three species have been identified: Manta birostris, Manta ehrenbergii, and Manta raya, but they are quite similar to each other, and the last two may just be isolated populations. The genus Manta is sometimes placed in its own family, Mobulidae, but this article follows FishBase, and places it in the family Myliobatidae, with the eagle rays and their relatives.
Mantas have been given a variety of common names, including Atlantic manta, Pacific manta, devil ray, devilfish, and just manta. Some people just call all members of the family stingrays.
Mantas have recently been captured on film while breaching. This had been reported in the past, but without any conclusive evidence. In the last few years, sharks have also been photographed while leaping out of the water. As with sharks, the reason for this behaviour in rays is currently unknown.