Great white sharks are powerful ocean predators. Their formidable presence and ability to navigate vast ocean depths spark considerable curiosity. Understanding how deep these sharks can dive provides insights into their life in the ocean.
The Depths They Reach
Great white sharks primarily inhabit the upper ocean layers, typically within the epipelagic zone (up to 200 meters or 656 feet). However, they can make extensive vertical movements. A record dive was 1,200 meters (3,937 feet) by a shark named “Shack” near New Zealand. Other individual sharks have also been observed diving to approximately 4,000 feet.
During their migrations, great white sharks frequently undertake deep dives, often reaching depths of around 900 meters (3,000 feet). Scientists have documented specific diving patterns, such as diel vertical migration, where sharks descend to 350-500 meters during daylight hours before returning to shallower waters at night. Rapid oscillatory diving, involving repeated descents to 30-200 meters, is another observed behavior. These vertical excursions demonstrate their adaptability across different ocean layers.
Why Do They Dive So Deep?
Deep dives by great white sharks serve various purposes, with foraging being a primary motivation. They pursue deep-dwelling prey such as squid, tuna, and deep-water fish like opahs and pomfret. Many of these prey species exhibit vertical migration, rising to shallower waters at night and retreating to deeper zones during the day, which sharks follow. This strategy allows sharks to access food sources unavailable closer to the surface.
Thermoregulation also plays a role in their deep-diving behavior. Great white sharks possess the physiological ability to maintain a body temperature warmer than the surrounding water. By moving between warmer surface waters and cooler depths, they can regulate their internal temperature, allowing them to remain active and efficient hunters in diverse thermal environments. Diving into warm-water eddies can enable sharks to forage longer at depth, where biomass is abundant.
Deep dives are also associated with navigation during long-distance migrations, such as journeys between California and Hawaii or South Africa and Australia. These vertical movements may aid in navigating by detecting magnetic fields or utilizing ocean currents at different depths. Some deep-diving patterns, particularly rapid oscillatory dives, have been linked to mating behaviors, especially among male sharks.
Unveiling Their Deep-Sea Secrets
Scientists employ advanced technologies to study the elusive deep-diving habits of great white sharks. Satellite tagging is a primary method, involving attaching transmitters to the shark’s dorsal fin. These tags transmit location data to satellites when the fin breaks the water’s surface, providing insights into their broad movements. Pop-up archival transmitting (PAT) tags also collect data on light, pressure, and temperature while attached, then detach at a programmed time and float to the surface to transmit their stored information.
Acoustic tracking provides another layer of detail. Sharks are fitted with acoustic tags that emit coded signals, which are then detected by strategically placed underwater receivers. This method allows for long-term monitoring of a shark’s movements, including its depth, temperature, and swimming speed, even when it remains submerged. Biologgers, instruments attached to the animal, log fine-scale movement and activity data for later retrieval. Analyzing collected data helps scientists reconstruct diving patterns and understand the environmental conditions sharks encounter.
Built for the Deep
Great white sharks possess several biological adaptations that enable them to undertake deep dives. They are considered regionally endothermic, meaning they can maintain a core body temperature warmer than the surrounding ocean water, unlike most other fish. This ability is facilitated by the rete mirabile, a specialized network of blood vessels that conserves metabolic heat generated by their muscles. A warmer body temperature allows for enhanced muscle efficiency and sustained activity in colder deep waters.
Their torpedo-shaped bodies are highly streamlined, reducing drag and allowing for efficient movement through the water column. Powerful tail muscles provide the thrust needed for rapid vertical movements. Great white sharks also utilize their large, oil-filled livers to regulate buoyancy. This adaptation allows them to ascend and descend with relative ease, conserving energy during their vertical excursions through varying depths.