Region: Philippines

Appearance
With a caudal fin or tail almost as long as the rest of its body, the zebra shark can be up to 11.5 feet (3.5 m) long. While it doesn't look like a zebra as an adult, the juvenile zebra shark has the zebra-like stripes. The young zebra sharks are black with yellow stripes. As adults, this shark has a yellowish-brown body with dark brown spots all over. A few ridges run down the length of the dorsal or back side of the body.

The snout or nose of the zebra shark is large, but the mouth is small. Barbels hang from the nostrils on the end of the snout. They help the shark to sniff out prey. The eyes are tiny and located on the sides of the head. Spiracles, which bring water to the gills, are located right behind the eyes.

Habitat
During the day, zebra sharks can usually be spotted resting on the sandy and rubbly ocean floor around coral reefs. This shark lounges in relatively shallow waters at depths of 17 to 100 feet (5 to 30 m). Propped up on its pectoral fins or the pair of fins on the side of the body behind the gills, zebra sharks sit with their mouth open facing the current. Scientists believe this behavior helps the shark breath while resting. Small fish are often found hanging out with the zebra shark and the bluestreak cleaner wrasse is often found picking off dead skin and parasites. Zebra sharks are loners, hanging out on the reef by themselves.

Young zebra sharks hide from predators in waters deeper than 165 feet (50 m).

Range
These sharks live in the warm waters of the Pacific Ocean, Indian Ocean and the Red Sea.

Diet
Zebra sharks are slow swimmers and not able to chase down fast prey. But these animals still eat well. With a flexible body, they wiggle into the narrow cracks, crevices and holes in reefs and devour the animals hiding inside. These sharks are nocturnal meaning they feed at night, mostly on snails and clams, but will also eat small fish, crabs and shrimp. Their mouth is filled with small teeth, which have three spikes—one large spike in the middle flanked by two smaller one.

Located on the bottom part of the head, the jaws of the mouth actually retract up into the head when it's swimming. This helps streamline the shark, making it swim faster through the ocean. Spotting something to eat, the zebra shark's jaw juts out and drops down, getting ready to scoop up its next victim.

Reproduction
Zebra sharks are oviparous. This means the pups or baby sharks develop outside of the body. The eggs are protected by leathery egg cases with hairy-looking fibers all over the outside which helps to attach the egg case to corals or seagrass and keep it from floating away. The egg cases are a purple/brown color and can be about 8 inches (20 cm) long. Zebra sharks will lay about four eggs at a time.

Back to top

Threats and Management
Fishers catch zebra sharks for their meat, which is eaten fresh or dried salted like jerky. The rest of the body is made into fish food. The oily liver of this animal is used to make vitamins. Its fins are used for soup or in the traditional Chinese medicine trade.

Sharks play a crucial role in reef and ocean ecosystems. They prey on weak and diseased animals. Human choices and human interference cause their numbers to decline. Some countries manage their coastal waters to protect sharks. But others have lax fishing laws, or too few resources to enforce laws that exist. In these places, shark populations suffer.

Sharks also suffer in the popular media, which often portray them as people-eating monsters. In reality, sharks don't attack people very often. When they do, it may be because they've mistaken a person for some other prey. Each year, sharks kill an average of eight people worldwide-yet people kill millions of sharks. More importantly, a decline in shark numbers affects the well-being of the entire reef ecosystem.

Fishing boats search the seas for target animals, like tuna, and discard anything else they accidentally catch—like sharks. The unwanted animals, called by-catch, dry out or suffocate on the deck, or get thrown back into the ocean all but dead. Each year, the worldwide fishing industry discards about a third of its total catch. This waste, or by-catch, not only pollutes the ocean but also creates extra work on fishing boats and ruins nets.

Sharks reproduce slowly, bear few young at a time, have a long gestation period, and many swim great distances to find a mate. That's why it takes years for their populations to rebound after a serious decline from overfishing.

FAO (Food and Agriculture Organization of the United Nations) member countries have been working for about a decade to create a plan of action for the conservation and management of sharks throughout the world. Many participating countries have been successful in their efforts. However, the vast size of the ocean and the lack of law enforcement in many areas maintain poor conservation and management of sharks globally.

Did You Know?
The zebra shark is the only member of its Family (Stegostomatidae).

The zebra shark is often confused with the leopard shark, a smaller, cold water shark.

References
Web Sites:
NOTE: The following Web sites are not maintained by the John G. Shedd Aquarium and will open in a new browser window.

Fishbase:
http://filaman.uni-kiel.de/Summary/SpeciesSummary.cfm?
ID=5374&genusname=Stegostoma&speciesname=fasciatum

Ichthyology at the Florida Museum of Natural History - Sharks: http://www.flmnh.ufl.edu/fish/sharks/sharks.htm

Print Publications:
Dozier, T.A. 1977. Dangerous Sea Creatures. United States of America: Vineyard Books, Inc. 128p. ISBN# 0-913948-04-7.

Michael, S.W. 1993. Reef Sharks & Rays of the World. A guide to their identification, behavior, and ecology. Petaluma, California: Sea Challengers. 107p.
ISBN# 0-930118-18-9.

Perrine, D. 1997. Mysteries of the Sea. Lincolnwood, Illinois: Publications International, Ltd. 312p. ISBN# 0-7853-2430-5.

Tricas, T.C., Deacon, K., Last, P., McCosker, J.E., Walker, T.I. and Taylor, L. 1997. Sharks & Rays. The Nature Company Guides. McMahons Point, Australia. 288p. ISBN# 0-7835-4940-7.

Back to top

Vocabulary Words

Barbels - Flaps of skin near the mouth used in tasting and feeling.


By-catch - The part of the fisher's catch which is returned to the sea either because it has no value to them. Fishing boats search the seas for target animals, like tuna, and discard anything else they accidentally catch-like sharks. The unwanted animals, called by-catch, dry out or suffocate on the deck, or get thrown back into the ocean all but dead.


Caudal - Having to do with the end or tail of an animal. The tail fin.


Dorsal - The back of an animal. The large fin on the back of a shark; the fin that sticks out of the water when a shark swims near the surface.


Egg case - A leathery protective container that enables shark eggs to mature until hatching.


Extinction - An organism that has not been present on the face of the earth for over 50 years.


Nocturnal - Active at night.


Organism - A living thing.


Overfishing - The excessive fishing or catching of aquatic (ocean or freshwater) animals to the point that the amount of animals being caught is greater than the amount of animals born. When more animals are caught than are being born, the aquatic environment is left depleted of the targeted animals.


Oviparous - A form of reproduction in which the young, or in this case pups, develop outside the mother's body inside thin leathery egg cases. Each pup receives food from a yolk sac inside the egg case. After the pups fully develop, they hatch from their egg cases.


Pectoral - The paired fins on the sides of a fish behind the gills.


Pup - A baby shark.


Snout - The pointy part of the head; similar to our nose.


Species - A group of organisms capable of breeding and producing fertile offspring; organisms that share the same gene pool.


Spiracles - A pair of holes, often located right behind the eyes, which bring water to the gills.


Streamlined - Having a torpedo shape which helps the animals efficiently move through the air or water.


Traditional Chinese medicine - A form of medicine practiced predominantly in China, Hong Kong, Taiwan, and Singapore, and by people worldwide. It is based on two counterpart, yin and yang. People get sick when the balance between yin and yang shifts. Natural elements, such as seahorses and other sea creatures, are used to heal disease.

Back to top