Bull Shark: Carcharhinus leucas
Common name
Lake Nicaragua Shark, river shark, freshwater whaler, estuary whaler, Swan River Whaler, cub shark, shovel-nose shark, Zambezi Shark, Zambi Shark, Ganges River Shark, Fitzroy Creek Whaler, Van Rooyen’s Shark, Lake Nicaragua Shark
Taxonomy
Kingdom Animalia
Phylum Chordate
Class Chondrichthyes
Subclass Elasmobranchii
Order Carchariniformes
Family Carcharinidae
Genus Carcharinus
Species: C. leucas
Identification
Bull sharks are renowned for their “bull-headed” appearance and aggressive tendencies. Its mouth is larger than its relatively small, stubby nose. The second dorsal fin is much smaller, whereas the first dorsal fin is tall and has a pointed tip. Its belly is white, and its back is a dark grey color. The typical male would be 200 pounds and roughly 7 feet tall. Females can reach lengths of over 11 feet and weigh around 500 pounds.
Life History of the Bull Shark
Cladodonts, the ancestors of sharks, are thought to have emerged from the warm oceans some 400 million years ago. By the end of the Cretaceous epoch (135–65 mya), when the last species of cladodonts vanished, sharks known as the Carchariniformes existed, exactly like they do today. (1984, Blasingame).
Diet of the Bull Shark
Bull sharks consume a variety of foods, such as rays, sea turtles, carrion from mammals, mantis shrimp, squid, crabs, sea urchins, sea snails, and even trash! Third, Anonymous (2006) It has been reported to kill hippopotamuses, terrestrial animals like antelope, livestock, dogs, and humans in the rivers. 1989 (Gold et al.).
Reproduction of the Bull Shark
Bull sharks typically breed in the water near river mouths in the late summer and early fall. They are viviparous marine creatures that give birth to baby sharks, or pups, in a manner similar to that of humans and other mammals. A bull shark fetus will gestate for 12 months before giving birth. They can grow to be up to 4 feet long at birth and are perfectly capable of taking care of themselves. They can frequently be seen close to river mouths and in shallow bays. They could be mature at 15 to 20 years old (Blassingame, 1984).
Habitat of the Bull Shark
They are widespread along tropical shorelines and occasionally found in rivers and lakes where freshwater and saltwater mix. They are found all over the world in a variety of habitats. These are the only sharks that have been shown to possess the extraordinary capacity to flourish in both fresh and salt water, allowing them to traverse great distances in the rivers. 1989 (Gold et al.). They can be found in the Mississippi River, the Amazon River, the Rio San Juan, Lake Nicaragua, the Bombay River, the Zambezi River, the Congo River, the Brisbane River, Lake Jamoer, and the Panama Canal, as well as the Ohio River in Indiana and Illinois. They spend up to a week swimming in freshwater. They might reside in freshwater due to breeding. In both freshwater and saltwater, their excretory system is modified to keep their osmotic pressure at a level that prevents dehydration (Steel, 1985).
They are widespread along tropical shorelines and occasionally found in rivers and lakes where freshwater and saltwater mix. They are found all over the world in a variety of habitats. These are the only sharks that have been shown to possess the extraordinary capacity to flourish in both fresh and salt water, allowing them to traverse great distances in the rivers. 1989 (Gold et al.). They can be found in the Mississippi River, the Amazon River, the Rio San Juan, Lake Nicaragua, the Bombay River, the Zambezi River, the Congo River, the Brisbane River, Lake Jamoer, and the Panama Canal, as well as the Ohio River in Indiana and Illinois. They spend up to a week swimming in freshwater. They might reside in freshwater due to breeding. In both freshwater and saltwater, their excretory system is modified to keep their osmotic pressure at a level that prevents dehydration (Steel, 1985).
Behavior
Bull sharks typically hunt alone, but they occasionally hunt in couples. They have significant levels of hostility against both humans and other animals and can cruise through shallow waters with swift acceleration. They are renowned for their erratic, frequently nimble, and aggressive behavior. It’s common to observe young sharks spinning out of the water (Compagno et al. 2005). They are thought to be significantly more at fault for human attacks than great white and tiger sharks are (Gold et al. 1989).
Recent research
According to a recent study on bull shark vision, their eyes aren’t made to distinguish between the various shades of water. They might only have the ability to see in black and white. Their retinas only possessed one type of cone (or light detector), which could distinguish between light and dark. Red, green, and blue are the three distinct colors that humans’ three different cones can distinguish. For them to recognize and identify objects, brightness contrast is crucial, which causes a misperception about assaulting others. Some think that sharks bite for a taste to confirm the thing in their field of vision since they believed people to be giant species of fish. According to information from the International Shark Attack File (ISAF), most attacks occur on surfers and divers wearing black wetsuits. The most recent discovery might be helpful in developing swimming and surfing gear that deters sharks and lessens human attacks. 2011 (Alleyne).
Economic/ecological service
- The 1916 shark attacks at the Jersey Shore, which served as the basis for Peter Benchley’s novel Jaws, may have been caused by one or more bull sharks. The novel was later recognized as one of Steven Speilberg’s best and most successful films. (1984, Blasingame).
- Bull sharks are frequently caught as prizes and eaten by people. Its meat can be eaten fresh, frozen, or smoked, and their fins are frequently used in expensive shark fin soups in China. Leather can be made from their hide after the scales have been removed. Their livers contain vitamin A-rich oil. Its skin can be used to create a very large, fine sandpaper. Their teeth are frequently used in jewelry. The International Union for Conservation of Nature and Natural Resources has it on its Red List as a near endangered species (3. Anonymous, 2006.)
- In Australia, young bull sharks are occasionally discovered being consumed by saltwater crocodiles. (2007) Underwater Times News Service.
- Common ectoparasites called copepods typically feed on the bull sharks’ skin tissues, particularly on the surfaces of their tail fins. The action of the copepods as a bait to attract prey is thought to represent the mutualistic symbiosis (Stevens, 1987).
