Dolphins are intelligent marine mammals and active predators found in diverse aquatic environments. Understanding their diet and hunting methods provides insight into their adaptability and ecological role.
What Dolphins Primarily Eat
Dolphins primarily consume a diet of fish and cephalopods, such as squid, octopus, and cuttlefish. Their specific food sources can vary considerably based on the dolphin species, geographical location, and whether they inhabit coastal waters, open oceans, or even freshwater rivers.
For example, common bottlenose dolphins, found worldwide, typically feed on fish like mackerel, herring, and cod, alongside squid. Some bottlenose dolphin populations in coastal areas might prefer local fish such as mullet, sea trout, or flounder.
Deep-sea dolphins often include squid and jellyfish in their diet, while river dolphins, like those in the Amazon or Indus, consume freshwater fish such as catfish and carp, as well as crustaceans and occasionally small reptiles. This flexibility highlights their opportunistic feeding, as they consume readily available prey.
An average-sized dolphin may consume up to 5% of its body weight in fish daily, with nursing mothers requiring even more.
Dolphins possess conical teeth designed for grasping prey rather than chewing. They swallow food whole or in large pieces and have a multi-chambered stomach for digestion. For larger or spiny fish, bottlenose dolphins may shake them, rub them on the ocean floor, or strip meat to manage their ingestion.
How Dolphins Hunt and Feed
Dolphins employ sophisticated techniques to locate and capture prey, leveraging both individual abilities and cooperative strategies.
Echolocation is a primary hunting tool, a biological sonar system. Dolphins emit high-frequency clicks and interpret the echoes that bounce back from objects, allowing them to determine the size, shape, speed, and distance of potential prey, even in murky or dark waters. Clicks are produced in their nasal passages and focused through a fatty organ called the melon. Echoes are received by fat deposits in their lower jaw and transmitted to the brain for interpretation.
Many dolphin species engage in cooperative hunting to increase success. One well-known method is herding fish into “bait balls,” where a group of dolphins encircles a large school of fish, forcing them into a dense, confined mass. Dolphins then take turns charging through the ball to feed.
Another specialized technique is “mud-ring feeding,” observed in bottlenose dolphins in Florida. A dolphin creates a circular wall of mud by rapidly moving its tail along the seafloor, disorienting and trapping fish within the ring. Other dolphins, or the same one, then consume the fish as they attempt to jump out.
“Strand feeding” is another unique cooperative method used by Atlantic bottlenose dolphins in specific coastal areas. Dolphins work together to herd fish onto muddy creek banks, then intentionally and temporarily beach themselves to catch the stranded prey before wriggling back into the water. Their streamlined bodies and powerful tail flukes are physical adaptations that aid in pursuing prey at high speeds and executing these precise maneuvers.