The great white shark, Carcharodon carcharias, is an apex predator inhabiting the coastal surface waters of all major oceans. It is the largest macropredatory fish in the world. This article explores its life stages, from reproduction to its role in marine ecosystems.
Reproductive Biology
Great white sharks reproduce through internal fertilization, with males using specialized organs called claspers to transfer sperm into the female’s cloaca. While the exact mating rituals remain largely undocumented, it is believed that the male may hold the female with his teeth during insemination, sometimes leaving behind mating scars.
The species is ovoviviparous, meaning fertilized eggs hatch inside the mother’s uterus, where pups develop. Early in development, embryos are nourished by a yolk sac. As they grow, they transition to consuming unfertilized eggs (oophagy), and in some cases, may even consume smaller, less developed siblings through embryophagy. Some research suggests a lipid-rich “uterine milk” secreted by the mother’s uterus provides additional nourishment during the early gestation period, prior to oophagy. The gestation period for great white sharks is estimated to range from 12 to 22 months. Due to this lengthy pregnancy, females are thought to reproduce only once every two to three years.
Birth and Early Life
Great white shark pups are typically born in coastal nursery areas, providing abundant prey and protection from larger predators. Known nursery locations include the waters off Long Island, New York, and southern California. These environments allow young sharks to hone hunting skills and reduce vulnerability.
A female great white shark generally gives birth to a litter of 2 to 10 pups, though litters of up to 17 have been recorded. At birth, pups are large, measuring 4 to 5 feet (1.2 to 1.5 meters) and weighing 60 to 77 pounds (35 kilograms). This size helps increase their survival chances in the open ocean. Pups are entirely independent at birth, receiving no parental care and immediately swimming away. Their initial diet consists of smaller prey such as fish, stingrays, and squid.
Growth to Adulthood
Following birth, great white sharks grow by about 25 centimeters (9.8 inches) annually. As they grow from juveniles into sub-adults, their dietary preferences shift. Young sharks primarily feed on fish and smaller shark species. However, as they mature, their diet expands to include larger prey, such as marine mammals like seals and sea lions, and other animals like crustaceans, mollusks, and seabirds.
Their habitat preferences also change with age; juveniles stay in shallower, nearshore waters, while older sharks frequent seal and sea lion rookeries and pelagic, open ocean environments. Great white sharks are highly migratory, undertaking extensive journeys across ocean basins. Reaching sexual maturity is a protracted process for these large predators. Males typically mature at 26 years, while females reach maturity later, at 33 years, according to recent studies. This maturation also correlates with size, with males becoming reproductively active at 3.4 to 4.0 meters (11.5 to 13 feet) and females at 4.5 to 5 meters (15 to 16 feet). Adult male great white sharks average 3.4 to 4.0 meters (11 to 13 feet), while females are larger, averaging 4.6 to 4.9 meters (15 to 16 feet). The largest females can exceed 6.1 meters (20 feet) and weigh over 1,800 kilograms (4,000 pounds).
Lifespan and Ecological Role
The great white shark has a long lifespan, estimated at 70 years or more, considerably longer than previous assumptions of 25 to 30 years. Some studies indicate individuals living up to 73 years. This longevity sustains their position as an apex predator.
As the top predator in their marine habitats, great white sharks play a significant role in maintaining ocean ecosystem balance. They regulate populations of their prey, contributing to the health and stability of the marine food web. The only known natural predator of the great white shark is the orca.