The great white shark, a formidable ocean predator, is often perceived as an “apex predator,” unchallenged at the pinnacle of the food chain. While this perception holds true, the question of what, if anything, preys on this species is more nuanced than commonly believed.
The Great White Shark’s Position in the Ocean
An apex predator is an animal positioned at the top of its food chain, generally lacking natural predators. The great white shark exemplifies this role due to its physical attributes and hunting prowess. Adult females average 4.6 to 4.9 meters (15 to 16 feet) in length, while males typically measure 3.4 to 4.0 meters (11 to 13 feet), with some individuals reaching up to 6 meters (19.7 feet) and weighing over 2,000 kilograms (4,400 pounds). Their robust, torpedo-shaped bodies, conical snouts, and serrated teeth enable bursts of speed up to 25 kilometers per hour (16 mph) and efficient hunting. These sharks can also maintain a body temperature higher than the surrounding water, which enhances muscular performance.
Great white sharks possess acute senses, including electroreception, allowing them to detect faint electrical fields generated by prey. Their diet is diverse, primarily consisting of marine mammals such as seals, sea lions, dolphins, and whales, particularly targeting their lipid-rich blubber. Younger sharks typically feed on fish before transitioning to larger prey as they mature. By consuming older, weaker, or sick individuals, great white sharks help regulate prey populations and contribute to the overall health and balance of their marine habitats.
Orcas A Unique Threat
While the great white shark reigns supreme in many ocean territories, the orca, or killer whale, stands as a unique natural predator. Orcas are highly intelligent and social animals that often hunt cooperatively in pods, a strategy that allows them to overpower larger prey. They employ sophisticated tactics, including ramming their targets and flipping sharks upside down to induce a state known as tonic immobility. This trance-like condition renders the shark temporarily paralyzed and defenseless, making it vulnerable to attack.
Orcas often target the great white shark’s liver, which is exceptionally rich in lipids and can constitute up to one-third of the shark’s body mass, providing a highly nutritious meal. Documented instances of orca predation on great whites include observations from the Farallon Islands in 1997 and 2000, where an orca was seen holding a white shark inverted, leading to its suffocation. Specific orcas, such as “Port” and “Starboard” off South Africa, have also been linked to multiple great white shark fatalities, with confirmed cases emerging from Australia in 2023 and 2024. While these interactions are significant and demonstrate the orca’s capacity to predate on great whites, they are not widespread occurrences across all great white shark populations. Great white sharks have also been observed to avoid areas where orcas are present, suggesting an avoidance strategy.
Human Activities and Their Impact
Despite having few natural predators, great white shark populations face primary threats from human activities. These impacts contribute significantly to the species’ conservation status, currently listed as vulnerable globally by the International Union for Conservation of Nature (IUCN). Great white sharks are particularly susceptible to these pressures due to their slow growth rates, long lifespans, and delayed reproductive maturity.
One major threat is bycatch, the unintentional capture of sharks in commercial fishing gear, such as gillnets and longlines, set for other species. This accidental capture is a leading cause of death for young great white sharks. Historically, targeted fishing for their fins, jaws, and meat also posed a significant danger, and illegal fishing continues in some regions despite protective measures.
Habitat degradation also plays a role, with pollution, coastal development, and the destruction of critical breeding and feeding grounds affecting their survival. Juveniles rely on sensitive areas like estuaries and mangroves, which are increasingly impacted by human activities and contaminants such as mercury and PCBs found in their tissues. Climate change, leading to rising ocean temperatures, forces great white sharks to shift their geographical ranges. This can alter prey distribution and potentially lead to new and unforeseen ecological interactions, further stressing these already vulnerable populations.