Dolphins are highly intelligent marine mammals that belong to the family of toothed whales, or odontocetes. They are classified as obligate carnivores, meaning their physiology is specifically adapted to consume a diet consisting exclusively of animal matter. This high-protein diet is necessary for their survival in the marine environment.
Dietary Classification
Dolphins are not fish, but are warm-blooded, air-breathing mammals that nurse their young. This biological status places them within the order Cetacea, alongside whales and porpoises. As members of the suborder Odontoceti, or toothed whales, their digestive systems are specialized for processing protein and fat obtained from other animals. Their metabolic needs require a high-energy diet that is met by consistently hunting and consuming prey.
Primary Prey Sources
The “meat” that constitutes a dolphin’s diet is primarily composed of various species of fish and cephalopods, though the specific menu varies significantly by species and geographic location. For most coastal bottlenose dolphins, the diet heavily features small schooling fish such as herring, mackerel, and sardines. In certain coastal regions, species like pinfish, pigfish, and hake are frequently targeted. Deep-diving species and those in offshore habitats often consume high volumes of energy-rich cephalopods, including squid and octopus.
The diet is largely opportunistic, meaning dolphins will adapt their feeding to the most abundant and easily accessible prey in their territory. Some dolphins also opportunistically consume crustaceans, such as shrimp and crabs, or even small marine turtles, depending on local availability.
Sophisticated Hunting Strategies
Dolphins utilize an array of complex and cooperative behaviors to secure their carnivorous diet, relying first on their highly developed sense of echolocation. This biological sonar involves emitting high-frequency clicking sounds and then interpreting the echoes that bounce back from objects, allowing the dolphin to form a detailed acoustic image of their underwater surroundings. Echolocation is particularly effective for locating prey, even in murky water or complete darkness, providing a precise tool for pursuit.
Many dolphin species engage in cooperative hunting, a display of social intelligence where pods work together to maximize their foraging success. A common strategy is “bait-balling,” where a group of dolphins encircles a large school of fish, driving them upward and inward into a dense, confined sphere. Individual dolphins then take turns darting through the disorganized mass to feed on the stunned or trapped fish.
In shallow, muddy areas, some populations of bottlenose dolphins have developed a technique called “mud-ring feeding.” A dolphin will rapidly swim in a circle around a group of fish, using its tail fluke to stir up a plume of mud that forms a temporary, circular net. The confused fish, attempting to escape the visual barrier, will leap out of the water directly into the waiting mouths of the other dolphins.
Another specialized technique is strand feeding, observed in places like South Carolina, where dolphins cooperatively drive schools of fish onto a mud bank or beach. The dolphins momentarily beach themselves to snatch the stranded prey before quickly wriggling back into the water. Dolphins use their conical teeth only for grasping and holding their slippery prey, which they generally swallow whole rather than chewing.