Great white sharks are powerful predators, and breaching is one of their most dramatic behaviors. Breaching is defined as the act of a shark propelling its body fully or partially out of the water and into the air. This spectacular leap displays immense speed and power, raising the question of why such a massive animal expends the energy to leave its domain. The primary driver for this behavior is a specialized hunting strategy.
Breaching as a Hunting Strategy
The most recognized reason great white sharks breach is to execute a vertical ambush attack on fast-moving prey at the surface. This strategy is often observed in False Bay, South Africa, where great whites target Cape fur seals. The shark uses the deep, dark water beneath the colony as a cloak, approaching from below where the prey is silhouetted against the surface light.
The attack involves rapid, vertical acceleration, often starting from depths around 20 meters. A great white’s body is built for straight-line speed; approximately 95% of its muscle is white muscle, which provides explosive bursts of power but poor endurance. This physical makeup necessitates a swift, decisive strike to avoid a prolonged, energetically costly chase.
Researchers estimate the shark can reach its target in roughly 2 to 2.5 seconds, achieving speeds of up to 40 kilometers per hour. The immense upward momentum from this acceleration is what launches the shark clear of the water, sometimes propelling it over three meters into the air. This tactic maximizes stealth and minimizes the prey’s reaction time, often giving a seal only about 0.1 seconds to respond once the shark is visible.
Alternative Behavioral Functions
While hunting is the most common cause, breaching is not exclusive to predation and serves other functions. Breaching is seen in many shark and ray species, suggesting its purpose is varied. For some sharks, the forceful impact of re-entering the water may dislodge external parasites or remoras attached to their skin.
Breaching may also be a form of communication, though this is less understood in great whites. The massive splash and sound created by the shark hitting the water could signal dominance, mark territory, or attract or repel other sharks. Additionally, some breaches relate to environmental surveying, similar to “spy-hopping.” This involves the shark lifting its head and part of its body out of the water to gain a visual of the surroundings.
How Scientists Study Breaching
Observing a natural breach is rare and unpredictable, so scientists developed specific methods to study this behavior. The most famous technique involves towing a seal-shaped decoy behind a boat in areas known for high great white activity, such as Seal Island near Cape Town. This decoy simulates a seal swimming at the surface, provoking the vertical ambush attack.
Researchers use high-speed photography and video analysis to capture the entire sequence, measuring the shark’s speed, angle of ascent, and the height of the breach. Scientists have also deployed specialized camera rigs to capture simultaneous footage of the shark’s actions both below and above the water. This allows for a detailed understanding of the shark’s decision-making process during the final moments of its ascent.