sand tiger shark
A: Sharks developed in salt water and are adapted to live there. While most species have to live in salt water, some sharks can live for long periods of time in freshwater. Bull sharks travel far into freshwater rivers and lakes. They have been found in the Mississippi River and in the freshwater Ganges River in India, the Zambezi River in Africa nd Lake Nicaragua in South America.
A: Scientists often age an animal by looking at the enamel growth layers on the animal's teeth. This method does not work very well for sharks since most of them lose their teeth every seven to 21 days. Just recently, marine biologists began tagging or tracking some shark species. Early research shows that slow growing sharks, such as the tope shark and the piked dogfish, can live more than 40 years.
A: Scientists at Sea World have learned that a shark eats about one percent to 10 percent of its total body weight per week. That means a 300-pound (9135 kg) shark may eat as little as 12 pounds (5.4 kg) of food a month. Humans use food to generate body heat. Since sharks are cold blodded, they don't need food to ehat their body. Sharks also are very efficient swimmers, using little energy (energy they would get from food) to swim about.
A: As a group, sharks eat almost anything: fishes, crustaceans, mollusks, marine mammals, and other sharks. Some sharks are filter feeders. The basking shark and megamouth shark strain huge amounts of plankton from the water on gill rakers. Whale sharks also filter feed. They strain plankton through a spongy tissue in their mouth. Filter feeding sharks have tiny, nonfunctional teeth.
whale shark
A: Sharks have a very streamlined shape. This shape is good for swimming and helps keep the shark buoyant or afloat. A shark's tail or caudal fin moves them forward and downward. The side or pectoral fins provide lift much like the wings of an airplane. Also, because sharks don't have any bones they are very light in the water. And, a shark's liver stores oils and fatty acids which also provide buoyancy.
Only 32 species of sharks have ever attacked people. There are more than 350 species of sharks.
A shark's entire skeleton is made of cartilage -- not bone. Touch your nose, it's made of cartilage too!
Most sharks have five different kinds of fins, which lift, stabilze and propel the shark.
SeaWorld/Busch Gardens Animal Information Database
www.seaworld.org / www.buschgardens.org
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