The bull shark is a unique and deadly fish living near coasts that are relatively close to the equator. These sharks, while not as large as the infamous great white, can still grow up to 11 feet (3.4 meters) long. Bull sharks can also weigh up to 510 pounds (230 kg). These numbers are close to the maximum recorded, and these amazing animals usually grow to around 7 feet 9 inches (2.4 meters) and normally weigh about 285 pounds (129 kg). These measures of length and weight are for the females, and the males are usually somewhat smaller. Bull sharks get their genus’s scientific name from two Greek words. The first of these is “karcharos”, which means sharpen. The other word is “rhinos” , meaning nose. When these two words are combined, they form the scientific name “Carcharhinus.” These words combined in English refer to these shark’s sharply pointed noses.
Bull sharks were made so that they blend into their surroundings. If you look at them from above, their dark topside blends into the dark ocean floor. If you look at them from the bottom, their light bottom-side blends into the sunlight. This body coloration helps them surprise attack prey without being noticed.
Although most sharks are found only in the ocean, the bull shark is unusual in that it can live in both freshwater and saltwater. Bull sharks have been found a ways upstream in both the Mississippi and Amazon rivers. On the Mississippi river, bull sharks have been found as far north as Illinois. Even the southernmost part of Illinois is about 560 miles (901 km) away from the base of the Mississippi River! They have also been found up to 1,870 miles (3,000 km) away from the sea in the Amazon river! Bull sharks can also withstand saltier water than normal. The saltiness of average ocean water is 3.5 percent, yet bull sharks can survive in water as salty as 5.3 percent. This is one and a half times the saltiness of average ocean water! These sharks have also been found in Lake Nicaragua in Central America. At first, scientists though the individuals in this lake were a different species because the rapids heading away from the lake made it seemingly impossible for sharks to get there from the ocean. This belief continued until the scientists found out that the sharks were – much like salmon – jumping over the rapids in order to get to the lake from the ocean.
Although bony fish and smaller sharks make up most of this animals diet, they are opportunistic predators and will eat basically anything they can that comes near. Bull sharks swim slowly around at the bottom of the ocean in shallow waters. When something catches a hungry shark’s eyes, it may swim at up to 11 miles per hour (18 kph) in order to catch its next meal.
Hunter or hunted?
Bull sharks are probably the most dangerous sharks to humans because of how close they live to the shore and the fact that they are aggressive. Although sharks in general are often called “man-eaters,” attacks by sharks are normally either because the shark is curious, or because the human aggravated the shark first. In fact, the main predator of bull sharks is humans. Sometimes fishermen will try to catch bull sharks, and in Asia these sharks are used in shark-fin soup. If a fisherman is able to get a bull shark caught on his line, he should be prepared to fight for hours if he wants to keep it.
Female bull sharks give birth to 1 to 13 live young after a ten to eleven month pregnancy. When young bull sharks are born in early spring or late fall, they are around 29 inches (75 cm) long. The births normally occur in freshwater lakes or rivers. During the first four years of their life they grow around 11 inches (28 cm) per year. After this, the growth rate is cut in half. They can also live for around 16 years for females and 12 years for males.
Don’t forget to scroll down to the bottom to leave your guess about what the next animal is and check out the coloring sheet under sources!
- Coloring sheet
- Animal: The Definitive Visual Guide. David Burnie and Don E. Wilson, Smithsonian Institution, ISBN: 978-0-7566-6002-4
- Bull shark: Wikipedia user: Walterince
- Mystery animal:Patrick connolly