Zebra shark

Natural History

Long and sleek, zebra sharks can wriggle into reef crevices and caves to hunt for their favorite food. Barbels (fleshy feelers) on their snouts help them search for their prey. Zebra sharks hunt at night; in the daytime they usually rest quietly on the bottom, "standing" on their pectoral (side) fins.

Juveniles are dark brown with white zebralike stripes, but adults are tan with brown leopardlike spots, so this shark has at least three common names—zebra shark, leopard shark and zebra/leopard shark. Common names can be confusing, which is why we depend on scientific names for identifying animals and plants.

To reproduce, male sharks use claspers (modifications of the pelvic fins) to transfer sperm into the female's reproductive tract. The zebra female lays fertilized eggs in tough capsules covered with tufts of filaments, which attach the eggs to the seafloor.

Conservation

Zebra sharks are caught for their meat, which is eaten fresh, or dried and salted like jerky. Its fins are used for shark fin soup or in traditional Chinese medicines. In some countries, shark fin soup is an expensive delicacy that can cost $100 or more for one serving. After fisheries catch sharks, they often strip off the high-value fins and toss the rest of the shark overboard. The process is called "finning." Often, the shark is still alive and lies helpless on the seafloor until it dies. Worldwide trade in shark fins increased from 3,300 tons in 1980 to 12,900 tons in 2000.

To curtail this slaughter of sharks, the United States government passed a law in 2000 that forbids shark finning and possessing shark fins without shark bodies, and prohibits foreign fishing vessels from shark finning in the United States' exclusive economic zone (EEZ). Canada, Australia, Mexico and New Zealand are also managing shark fisheries, but more countries need to regulate these fisheries.

Cool Facts

If sharks stop swimming, they sink, since they don't have gas-filled swim bladders like most other fishes. Their oil-rich livers help with buoyancy but not enough to keep the sharks afloat. 

An albino zebra shark was discovered in 1973 in the Indian Ocean. She had a grayish tail, but was otherwise uniformly white without the usual dark spots seen on adults. Scientists were surprised she had survived, as her coloring would make her more vulnerable to predators.

To breathe, many sharks must swim to force oxygenated water over their gills. But, like all bottom-dwelling sharks, zebra sharks have the ability to pump water over their gills, either through their mouth or through the large spiracle behind each eye. To ease the task of pumping all that water over their gills, the sharks face into the ocean current.