The bottlenose dolphin, Tursiops truncatus, is a highly intelligent and exceptionally athletic marine mammal found in temperate and tropical oceans across the globe. This mastery of movement allows the bottlenose dolphin to achieve remarkable speeds, whether they are traveling lazily or chasing down fast-moving prey.
Maximum Burst Speed
The maximum speed a bottlenose dolphin can achieve is a short, temporary burst used for immediate necessities like evading a predator or rapidly closing the distance on a meal. These high-speed sprints are consistently recorded in the range of 20 to 22 miles per hour (32 to 35 kilometers per hour) for trained individuals. There have been reports and calculations suggesting speeds can momentarily exceed 30 miles per hour (48 kilometers per hour), particularly just before a high jump out of the water.
Typical Cruising Speed
In contrast to their maximum burst, the speed dolphins maintain for routine travel, foraging, and migration is significantly lower and much more energy efficient. The typical cruising speed for a bottlenose dolphin is generally between 3 and 7 miles per hour (5 and 11 kilometers per hour). Energetic studies indicate that the most efficient traveling speed for these dolphins, where the metabolic cost of transport is minimized, falls even lower, around 3.3 to 4.5 knots, or 6.0 to 8.2 kilometers per hour.
Factors That Influence Velocity
A dolphin’s swimming speed fluctuates constantly based on a combination of internal and external variables. The purpose of the movement is the single largest determinant of speed, with hunting or escaping requiring high speeds, while long-distance travel maintains a slow, steady pace. The health and age of the individual dolphin also play a role, as younger or less healthy animals cannot produce the same propulsive power as a mature, robust adult.
External factors, such as environmental conditions, significantly influence the speed a dolphin can maintain. Dolphins often engage in bow-riding, where they position themselves in the pressure wave created by a moving boat to get a “free ride,” effectively achieving higher speeds with minimal effort. At higher speeds, dolphins will also frequently engage in “porpoising,” which involves leaping clear of the water’s surface, a behavior that is thought to conserve energy by reducing the drag associated with swimming near the air-water interface.
The Mechanics of Dolphin Propulsion
The ability of the bottlenose dolphin to move so quickly and efficiently stems from a suite of highly specialized anatomical and physiological adaptations. Their body possesses a perfect fusiform, or torpedo-like, shape that is highly streamlined, minimizing the pressure drag created as they move through the water.
Propulsion is generated by the powerful, vertical up-and-down oscillation of the tail flukes, which contrasts with the side-to-side movement seen in most fish. The flukes themselves are not rigid; they are flexible, acting as hydrofoils that generate forward thrust on both the upstroke and the downstroke.
Scientists have found that the unique properties of the dolphin’s skin also contribute to its speed by managing the flow of water across its surface. The rapid shedding of skin cells helps to reduce friction drag by disrupting the formation of tiny whirlpools, or vortices, that would otherwise increase turbulence and slow the animal down. The dolphin’s overall hydrodynamics and intermittent swimming techniques, such as the fluke-and-glide gait, further enhance efficiency by reducing the mechanical cost of transport by nearly 30% compared to continuous fluking.