ASK THE AQUARIUM: Sharks Lose Teeth Frequently
Q. Do sharks lose teeth like people do?
A. They sure do. Surprisingly, sharks lose or break teeth easily, but the teeth are quickly replaced from a warehouse of five to 15 rows of spares continuously produced and stored in the shark's jaws. New teeth can move to the front within 24 hours to replace lost teeth. Some sharks can produce over 10,000 teeth in a lifetime. It's estimated that a tiger shark produces up to 24,000 teeth in a 10-year period!
Different sharks have different shaped teeth; some are long and curved for holding slippery fish, others are serrated for cutting. Some, like the smooth dogfish, have teeth designed for crushing.
Sharks can't chew food and must swallow it in chunks. They eat at one- to two-day intervals and are more active during twilight and night. Most feed on sick or injured animals, with diets varying from fish to stingrays to seals. However, the examination of the contents of one tiger shark's stomach revealed half a crocodile, a sheep's hind leg, three gulls, two cans of unopened peas and assorted bike parts. The basking shark, one of the largest sharks reaching 45 feet in length, has very small teeth and feeds exclusively on tiny plankton.
Shark teeth found on beaches are most likely not from sharks swimming today. They are fossilized, ranging from 20,000 to 50 million years old. The teeth are usually very dark, black or gray, but can be brown or creamy. Color variation is due to different environments and sediments in which they were formed. Size and shape vary with species. If the tooth is in fairly good condition, it can often be traced back to its owner.
The teeth of about 14 shark species are found on Carolina beaches. Among those are the great white, hammerhead, tiger, bull and lemon sharks. Good hunting grounds are Fort Macon State Park, Atlantic Beach; Topsail Beach near Jacksonville; and Hammocks Beach State Park near Swansboro. The best time for hunting is at low tide or after storms.
Visitors can also search for shark teeth and other ancient marine animal remains at on-site fossil digs at all three of the state's public Aquariums. Serious fossil hunters may want to visit the Aurora Fossil Museum on N.C. 306 in Beaufort County. For information, call the museum at 252-322-4238, or log on to aurorafossilmuseum.com.
Sharks are fascinating creatures, with an average natural life span of 25 years. Their biology has remained virtually unchanged for millennia; however, today their populations are declining. If overfished, their populations can remain depleted for decades because of slow growth and reproduction rates.
As top predators, sharks play a vital role in the health and balance of the marine ecosystem.
The state operates three public aquariums; one in Pine Knoll Shores, another at Fort Fisher and a third on Roanoke Island. The aquariums are administered by the North Carolina Department of Environment and Natural Resources, and are designed to inspire appreciation and conservation of North Carolina's aquatic environment.
For more information about the Aquariums, log onto www.ncaquariums.com, or call 800-832-FISH.
Sherry White works for the N.C. Aquariums.
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