Bull Shark (Carcharhinus leucas)

I. GEOGRAPHIC RANGE

• The bull Shark inhabits coastal waters in tropical and subtropical seas worldwide.

II. PHYSICAL CHARACTERISTICS

• Mass: 90 to 230 kg.
• The bull shark can be recognized by its unique body shape, which is much wider in comparison to its length than other sharks, and its snout, which is wider than it is long. These features give the bull shark an almost stout appearance.
• The shark is gray on the top half of its body and off-white underneath. Several individuals have been found with pale stripes on the sides of their bodies. The young sharks can be distinguished by the dark edges on their fins.
• The bull shark also has two dorsal fins, the second of which is much smaller than the first.
• Males of the species are approximately 7 feet long and weigh 90 kg while females grow to 11.4 feet on average and weigh 230 kg.

III. FOOD HABITS

• The bull shark is an omnivorous animal. It routinely preys upon fish, sharks (especially young sandbar sharks), rays, turtles, echinoderms, birds, mollusks, dolphins and almost anything else it can find. Remains of everything from humans to hippopotamuses have been found in bull sharks' stomachs.

IV. REPRODUCTION

• Bull sharks are viviparous, meaning they give birth to live young that are nourished inside the mother shark. Sexual maturity is reached between the ages of 8 and 10. Bull sharks breed in the summer months and the young sharks are born approximately one year later. The pups are born in litters of up to 13 and are around 28 inches at birth.
• A common breeding place for the bull shark is the brackish water where freshwater rivers meet the saltwater oceans.

V. BEHAVIOR

• The bull shark is a solitary species that hunts by itself.
• Most individuals are not migratory, however many bull sharks in South America have been known to migrate thousands of miles from the Amazon River to the Atlantic Ocean.
• The largest threat to the shark is the large number of humans who fish for it commercially. Other large sharks also prey upon bull sharks, especially in their juvenile stage.
• One interesting behavior is the bull shark's willingness to enter freshwater areas. The shark has been found far up the Mississippi and Amazon Rivers and also in Lake Nicaragua. Scientists thought the sharks in Lake Nicaragua were a separate species until they discovered that bull sharks were jumping the rapids, much like salmon, to enter the lake.

VI. HABITAT

• Although bull sharks have been caught in considerably deeper water, they most often reside in water between 30 meters and waist deep. The sharks also seem to favor murky water for hunting. It is one of the only sharks able to survive in freshwater for extended periods of time.

VII. ECONOMIC IMPORTANCE FOR HUMANS