Manta Ray

Rays

Ray is the common name for any of about 425 species of cartilaginous fishes found in almost all seas. Rays have broad, flattened bodies, with eyes located on the upper, dark colored surface of the body and with mouth and gills located on the lower, light colored surface. The pectoral fins are extremely well developed and extend from the tail to the sides of the head. The pelvic fins are relatively small, and the anal fin is absent, the tail region being reduced to a slender, whip-like organ that the ray uses as a rudder. The huge pectoral fins serve to move the fish through the water at a slow pace. Many rays, such as the stingrays and electric rays, have developed protective devices for defense against enemies. Rays have small mouths containing blunt teeth, adapted for crushing the shells of the mollusks and crustaceans on which they feed. The creatures inhabit the ocean bottom, often burying themselves in the sand when not in search of food. They can change colors to camouflage themselves. Some species lay eggs; in most species the young are born live.

Rays vary in size from a few centimeters to more than 6 meters (more than 20 feet) in width. The largest rays are known as devilfish, sea bats, or mantas; they attain a weight of more than 1360 kilograms (more than 3000 pounds).

The ray order includes the guitar fishes; the sawfishes; the skates; the stingrays; the devilfishes; the electric rays and the eagle rays.

Sawfish

Sawfish are rays that differ from most rays in being less broadly flattened. Sawfishes bring forth live young, rather than laying eggs. Their chief distinction is an elongate snout, which attains a length of almost 2 meters (almost 6 feet); the snout is studded with strong toothlike projections. The sawfish uses this structure as a weapon with which to slash disturbers and also obtain food. Adult sawfishes attain a total length, including saw, of from 3 to 6 meters (10 to 20 feet). They inhabit the shallow regions of tropical seas, being especially abundant off tropical America and Africa. The common sawfish is found from the Gulf of Mexico southward.

Skate

Skates are flat-bodied rays found in warm and temperate seas, including the coastal waters of the United States. The flesh of the European, or gray, skate, which attains a weight of 45 kilograms (100 pounds), is extensively eaten in Europe; skate flesh is not common in the American diet. The smallest and commonest of the skates found along the eastern coast of North America is the little, or hedgehog, skate, which attains a length of less than 60 centimeters (less than 2 feet) and is densely spotted with black on its upper surface. The big skate, found off the coast of California, is the largest of the American skates, attaining a length of about 2 meters (about 7 feet); the egg cases deposited by the female are almost 30 centimeters (almost 1 feet) long.

Stingray

Stingrays have broad, flattened pectoral fins that give them an almost diamond shape; in some species the fins are more than 1.5 meters (5 feet) wide. The long, finless, whiplike tail has one or more large, sharp, sometimes barbed spines at its base that are associated with poison glands and can inflict severe wounds-stingrays are, in fact, the most common cause of severe fish stings. They are ovoviviparous-that is, the female carries eggs that hatch at the time of birth.

Devilfish

Devilfish is the name applied to several marine animals, primarily to any large species of ray (also called manta). Devilfishes are found in temperate and tropical waters near continents and island groups of all oceans. These cartilaginous fishes, also called devil rays and sea bats, have greatly extended, wing-like pectoral fins. The largest, the Atlantic manta, can measure 7 meters (23 feet) from tip to tip of these fins. Like the devil ray, the Atlantic manta is characterized by a pair of forward-pointing lobes on each side of the head, with a presumed resemblance to a devil's horns. These lobes are used to guide plankton and small crustaceans into the fish's mouth as it cruises near the surface; dense gill rakers extract the plankton. The fish is harmless to humans, but its thrashing when caught can be dangerous.

A torpedo generates electricity from columns of stacked, platelike cells called electroplates that are organized into many small blocks of muscle on either side of its head. Nerves branching throughout the electric organs initiate the charge, which intensifies as it passes through the column. The torpedo wraps its pectoral fins around its prey, disabling it with a 200-volt shock.

Torpedo

The torpedo, also called electric ray, include several related rays that inhabit warm seas and often are of large size, reaching a length of up to 1.8 meters (up to 6 feet). The Atlantic torpedo, found on both sides of the Atlantic, is said to attain a weight of about 90 kilograms (about 200 pounds). These rays have a broad, flat body with a comparatively slender tail and are of interest because of the electrical powers that they possess. An electric organ consisting of plate-like cells derived from muscle tissue is found in each pectoral fin. These organs emit pulsed discharges that combine to deliver a shock of up to 200 Volts for about 1 second. The shocks enable torpedoes to stun faster-swimming fishes and also serve as a defense against predators. Once discharged, the rays require a rest period before they become charged again. The organs adapted for this purpose consist of groups of highly compact nerve endings.

Eagle Ray

The eagle ray family includes the cownose ray, the duck-billed ray, and the bat ray. The eagle ray may weigh as much as 360 kilograms (800 pounds). The fleshy pad around the front of its head distinguishes it from the other rays. The eagle ray's large, expanded, pectoral fins join its head to form a broad disk, and its flat teeth are adapted for feeding on shellfish. Near the base of its long, thin tail is a serrated spine that can inflict a severe wound. The eagle ray's young are born alive.

Scientific classification

Rays belong to the class Chondrichthyes.

Stingrays make up the family Dasyatidae. The freshwater stingrays of South America make up the family Potamotrygonidae. Sawfish make up the family Pristidae of the order Rajiformes. The common sawfish is classified as Pristis pectinata. Skates make up the family Rajidae of the order Rajiformes. The European, or gray, skate is classified as Raja batis, the little, or hedgehog, skate as Raja erinacea, the smooth, or barn-door, skate as Raja laevis, and the big skate as Raja binoculata. Devilfishes belong to the family Mobulidae. The Atlantic manta is classified as Manta birostris. The devil ray is classified as Mobula hypostoma. Torpedoes, or Electric rays, make up the family Torpedinidae of the order Rajiformes. The Atlantic torpedo is classified as Torpedo nobiliana. The eagle ray is a member of the family Myliobatidae, class Chondrichthyes. It is classified in the genus Myliobatis.