Rays

Rays

Cartilaginous Fish

SCIENTIFIC CLASSIFICATION

COMMON NAME: ray, stingray
KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Chondrichthyes
SUPERORDER: Batoidea
ORDER: Myliobatiformes
FAMILY: Dasyatididae (stingrays); Myliobatidae (eagle rays); Mobulidae (manta rays)
GENUS SPECIES: Approximately 480 species

FAST FACTS

DESCRIPTION: Rays in the order Chondrichthyes are essentially a compressed, flattened shark. The pectoral fins are fused to the head region into a disc and, in many species, the head is raised above the disc. Most species have a long, whip-like tail and many possess at least 1 venomous spine located along the tail. On the head region, large openings or spiracles lie behind the smaller eyes and 5 gill slits are located ventrally on each side.
MALE Male rays are easily distinguished from females by the presence of a pair of claspers (cigar shaped organs).
SIZE: A ray's wingspan, or disc-size, can range from about 30 cm (12 in.) in yellow stingrays to over 6.1 m (20 ft.) in manta rays.
WEIGHT: No data
DIET: Rays primarily feed on mollusks, crustaceans, worms, and occasionally smaller fishes. Manta rays filter feed mostly on small crustaceans and small schooling fish.
GESTATION: Ovoviviparous ("egg live birth")
SEXUAL MATURITY: No data
LIFE SPAN: No data
RANGE: Worldwide, particularly in tropical, sub-tropical, and temperate waters
HABITAT: Oceans, estuaries, freshwater streams, lagoons, lakes, shallow offshore waters, and coastlines
POPULATION: GLOBAL No data
STATUS: IUCN Spotted eagle ray and manta ray listed as Data Deficient; several stingray species listed (1 species Endangered, 1 species Vulnerable, 1 species Lower Risk/Near Threatened)
CITES Not listed
USFWS Not listed

FUN FACTS

1. All rays belong to the superorder Batoidea, which includes stingrays, electric rays, skates, guitarfish, and sawfish. Like sharks - their close relatives - batoids have skeletons made of tough connective tissue called cartilage.
2. Some rays crush their prey between their blunt teeth, sometimes referred to as bony plates. (The term "bony plates" is, however, a misnomer in that rays do not have bone, but rather, cartilage.) Often completely burying themselves in the sand or soft sediment, rays are camouflaged by a grayish-brown, often mottled coloration.
3. Reminiscent of birds in flight, some rays gently flap their enlarged pectoral fins, or "wings," to "fly" through and sometimes even leap out of the water. The wingspan, or disc-size, of a southern stingray (Dasyatis americana) can reach up to 1.5 m (5 ft.).
4. Among the best known rays are stingrays, which have long, slim, whiplike tails armed with serrated, venomous spines. A stingray lashes its tail only as a defensive measure when it is caught, stepped on, or otherwise disturbed.
5. When wading in shallow waters, people should shuffle their feet to avoid stepping on a buried stingray.
6. For more information about sharks & rays, explore the Sharks & Rays InfoBook.

ECOLOGY AND CONSERVATION

In many parts of the world, some rays are commercially important food sources, yet currently, rays are not considered threatened or endangered. Due to humankind’s impact on the marine environment, however, concern is mounting for the future of rays throughout their range.

BIBLIOGRAPHY

Burgess, W. and H.R. Axelrod. Pacific Marine Fishes. Book 4. Neptune City, NJ. T.F.H. Publications, Inc. Ltd. 1974.

Eschmeyer, W.N., Herald, E.S. and H. Hammann. Peterson Field Guide to Pacific Coast Fishes. New York. Houghton Mifflin Co. 1983.

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