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All About Sharks!
Geologic Time Chart
|Introduction to Sharks||Introduction to Rays||Anatomy||Shark and Ray Species||Extreme Sharks||Extinct Sharks||Classification||Shark Glossary||Shark Index||Printables, Worksheets, and Activities|
|What is a Ray?||Ray Printout|
| Rays range in size from just a few inches to over 22 feet wide. The smallest ray is the Short-nose electric ray, which is the size of a pancake; it is only 4 inches (10 cm) across and weighs about 1 pound (0.5 kg). The biggest ray is the manta ray which is over 22 feet (6.7 m) wide and weighs many tons (thousands of pounds).
Most rays are in-between these two extremes. More than half of all ray species are over 20 inches (50 cm) long. In fact, rays are some of the largest fish in the sea!
Manta birostris is the largest ray. This graceful swimmer is up to 29.5 ft (9 m) wide. Mantas eat microscopic plankton, small fish, and tiny crustaceans. They funnel the food into their mouth while they swim, using two large, flap-like cephalic lobes which extend forward from the eyes.
The Bluespotted Ribbontail Ray
Taeniura lymna is a very common, timid ray with an oval-shaped disc and two venomous tail spikes toward the tip of its tail. It grows to be 2.25 ft (0.7 m) long.
| Rays have a flattened body shape and an elongated tail. The pectoral fins are large and connected to the body to form the ray's "disc." The shape of the disc differs from species to species and may be circular, oval, wedge-shaped or triangular. Some body shapes are adapted for living on the sea bed; others are adapted for almost constant swimming.
The ray's distinctive tail also varies from species to species. It ranges from stubby (on the Shorttailed electric rays) to incredibly long (e.g., over 10 feet (3 m) long on the Whip-like sting rays).
Rays have no bones; their skeleton is made of cartilage.
|Rays and sharks are a type of fish that have no bones, only cartilage. Some parts of their skeleton, like their vertebrae, are calcified. Cartilage, a strong fibrous substance, is softer than bone; our nose and ears are made of cartilage.
Even the ray's skull is flattened.
Rays belong to the group of fishes called Elasmobranchii, which also includes the sharks, skates, and ratfish. The Elasmobranchii are all fish that have no bones, only cartilage.
|Rays defend themselves from predators in many ways. Some use a whip-like tail to lacerate an enemy, some sting enemies with a poisonous stinging tail, electrical rays give electrical shocks (up to 200 volts), and some have hard, bony spines that puncture their victims. Teeth are not used very much by rays as a defense, although some can bite. Camouflage on the sea bed is probably among their best defenses.
Rays do not normally attack people. There are some rays who have a tail sting that can be deadly.
Blind Electric Ray
Typhlonarke aysoni can give an electrical shock and has almost useless eyes. This poorly-known ray uses electroreceptors to "see." This numbfish has one dorsal fin and lives at great depths (200-900 m).
Rays and skates have a long gestation period and produces relatively few young (compared to other fish). The growth of ray populations, therefore, is slow.
Manta ray printout
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