The definitive answer is that dolphins do not eat coral. These intelligent marine mammals are obligate carnivores, meaning their diet is strictly composed of other animals, primarily fish and squid. The misunderstanding often arises from observations of dolphins swimming and foraging near reefs, which are rich hunting grounds.
Are Dolphins Built to Eat Coral?
Dolphin anatomy and physiology are specifically adapted for capturing and consuming soft-bodied prey, not for grinding hard, calcium carbonate structures like coral. As obligate carnivores, dolphins are equipped with a single set of conical teeth throughout their life, which are designed for grasping and holding slippery fish and cephalopods. These peg-like teeth are not suited for mastication or chewing, as the animals swallow their food whole.
Their digestive system further confirms their purely carnivorous diet, featuring a multi-chambered stomach that is specialized for processing whole, soft prey. The first chamber, or forestomach, acts as a holding area, while the second chamber is where chemical digestion begins with powerful enzymes and hydrochloric acid. This system is efficient at breaking down protein and fat from meat, but it is not adapted to digest the tough, cellulose-based or mineral-rich materials found in plants or coral skeletons.
The True Diet of Dolphins
The dolphin diet is highly varied, consisting mainly of fish, squid, and occasionally crustaceans, with the exact menu depending on the species and geographical location. Coastal species, such as the bottlenose dolphin, often consume bottom-dwelling invertebrates and a wide array of schooling fish like mullet and herring. Oceanic species tend to focus more on squid and deep-sea fish, reflecting the prey availability in their open-water environments.
Dolphins are skilled, cooperative hunters who use a range of sophisticated techniques to secure their prey. A primary hunting method is echolocation, where they emit high-frequency clicks and interpret the returning echoes to pinpoint the precise location and size of fish, especially in murky water or darkness. They also engage in coordinated social hunting, such as herding schools of fish into tight “bait balls” or using their tail flukes to slap the water, which stuns or disorients the prey. Some bottlenose dolphins even employ unique, learned techniques like “strand-feeding,” where they temporarily beach themselves to trap fish against a shoreline.
Why Dolphins Interact with Coral Reefs
Dolphins frequent coral reef environments not for the coral itself, but because the reefs are rich and complex habitats that serve as prime hunting grounds. Reef structures provide shelter for a vast number of small fish and invertebrates, effectively concentrating the dolphins’ prey in a predictable location.
Furthermore, the physical structure of corals and sponges is used by dolphins for hygienic purposes. Researchers have documented Indo-Pacific bottlenose dolphins repeatedly rubbing their bodies against specific corals and sponges. This behavior is thought to be a form of self-medication or skin maintenance, as the chosen invertebrates secrete a mucus containing active metabolites with antibacterial and antioxidative properties.