The tiger shark (Galeocerdo cuvier) is a large, widely distributed marine predator. It inhabits tropical and temperate waters globally, from coastal areas to the open ocean. Its common name comes from the distinctive dark stripes on its body, which fade as the shark matures. The tiger shark is an opportunistic hunter, known for its broad and varied diet.
The Tiger Shark’s Dominance
Adult tiger sharks are apex predators within their marine ecosystems. Their formidable presence stems from impressive size, with mature females often exceeding 5 meters (16 feet) and weighing over 900 kilograms (2,000 pounds). They possess powerful jaws armed with uniquely serrated teeth, designed to efficiently cut through flesh, bone, and even tough shells. They also have highly developed sensory organs, including electroreceptors that detect faint electrical impulses and a lateral line system that senses vibrations. These attributes, combined with their expansive diet, place the tiger shark at the top of the food chain in most habitats, meaning fully grown tiger sharks generally encounter no natural predators.
Natural Predators
Despite their dominant position, adult tiger sharks can rarely fall prey to other marine creatures. Killer whales, or orcas (Orcinus orca), are the only known significant natural predators of adult tiger sharks. These intelligent marine mammals employ complex, cooperative hunting strategies. Their superior size and coordinated attacks allow them to overpower even large sharks, sometimes specifically targeting them for their nutrient-rich livers.
Predation is more common for younger tiger sharks, which are more vulnerable due to their smaller size. Juvenile tiger sharks can be preyed upon by larger sharks, including other adult tiger sharks, a form of cannibalism observed in the species. Other large shark species, such as bull sharks and great hammerheads, also pose a threat to these smaller, developing individuals. While less frequent, great white sharks may occasionally prey on adult tiger sharks, though this is not a primary dietary component for them.
Human Influence
Human activities are the most substantial influence on tiger shark populations, far outweighing natural predation. Commercial fishing poses a considerable threat, as tiger sharks are caught both as bycatch and through targeted fishing. They are sought for their fins, meat, and liver oil, valued for its high vitamin A content. This fishing pressure, combined with low reproductive rates, makes tiger sharks susceptible to population declines.
Habitat degradation also impacts tiger sharks, stemming from pollution and coastal development that disrupt feeding and breeding grounds. Climate change, such as warming waters, can alter prey availability and force tiger sharks to expand ranges, leading to increased interactions with fisheries. These human-driven factors contribute to the tiger shark’s classification as “Near Threatened” by the IUCN.