Latin name

Carcharhinus leucas

Other names

Freshwater whaler, river whaler.

Identification

The Bull shark gets its name from its bull-like head and is known for its heavy body and short snout, which appears very broad and rounded underneath. Gray or dull brown above and pale below, the shark has a large first dorsal fin that begins above the middle pectoral fin, and the upper tail blade is much larger than the lower one.

Distribution

It is a species native to Lake Nicaragua in Nicaragua and has become known as a man-eater because it has been implicated in repeated attacks on humans. Also known as the Zambezi shark in South African waters, it is one of the three most dangerous sharks in this region, along with great white and tiger sharks, because of its abundance in coastal habitats where attacks on humans are more likely. Bull shark readily bites natural bait. Unlike other sharks that rise to the surface, it often stays in deeper water and wrestles hard. Bull sharks are widely distributed. They are found in the western Atlantic Ocean from Massachusetts to southern Brazil and in the eastern Pacific from southern Baja California, Mexico, to Ecuador and possibly Peru.

Habitat

Bull shark is also called freshwater whaler and river whaler because it is most often found in the coastal zone around river mouths and can adapt to life in fresh water.

Size

Usually growing to a length of 6 to 9 feet, it can reach 12 feet and weigh more than 500 pounds. The world record for all tackle was previously held by a 490-pound shark caught off the coast of Alabama in 1986, but it was surpassed in 2001 by a 697-pound shark caught off the coast of Kenya.

Life history and Behavior

Bull sharks are unique in their ability to inhabit both salt seawater and freshwater rivers and lakes. Juveniles typically stay in estuaries and coastal waters, moving to deeper waters as they mature. They inhabit tropical and subtropical coastal waters worldwide at depths of 1 to 150 meters (3–492 feet). Pregnant females often seek river estuaries for giving birth, where pups are safer.

This species is known for its aggressive and territorial nature.

For a long time, they were thought to lead solitary lives. However, recent research shows that they have complex social connections and hierarchies. They can form "friendly" pairs, swim synchronously ("parallel swimming"), and exhibit "leader-follower" behavior. They have been observed to prefer the company of individuals of similar size and sex, with adult sharks generally being more socially active than older ones.

Food and feeding habits

They are active predators, whose behavior includes both hunting strategies and surprisingly complex social interactions. Bull sharks are opportunistic apex predators. Their diet is extremely diverse: fish, rays, turtles, birds, dolphins, and even other sharks. Before an attack, they often use a characteristic head-butt.

Reproduction

Bull sharks are viviparous (live-bearing). The embryo develops inside the mother, feeding through a placenta formed from the yolk sac. Gestation lasts about 10–12 months, and the female gives birth to 1 to 13 pups. Birth usually occurs in late spring or early summer, depending on the region, and newborns are about 56–81 cm (22–32 inches) in length.

Females are generally larger and heavier than males, reaching up to 4 meters (13 feet) in length and weighing about 315 kg (694 lbs), while males typically grow to 3.6 meters (12 feet). Males reach sexual maturity at 9–10 years of age, at a body length of 160 to 234 cm (63–92 inches). Females mature later, at about 10–15 years, at a length of 180 to 257 cm (71–101 inches). The average lifespan in the wild is about 16 years, although in captivity they can live up to 30 years. According to research on sharks off Réunion Island, the reproductive cycle may be biennial, with sperm storage occurring between mating and fertilization.

Relationship with a person

The bull shark is considered one of the most aggressive and dangerous sharks to humans, and many experts rank it first on this list. It is believed that this reputation is due not so much to its bloodthirstiness as to its habitat. It lives where most people swim — in murky water in shallow areas, in river estuaries, and even far upstream (for example, in the Mississippi or Amazon). This leads to far more encounters with humans than other species. Unlike great whites, which often bite "test" and release, bull sharks tend to attack more decisively, including repeatedly, if they feel threatened or are defending their territory. Additionally, they have high testosterone levels, which, according to some, may influence their aggressiveness.