The question of whether dolphins prey on sea lions is complex, as the term “dolphin” encompasses nearly forty species of toothed whales with vastly different sizes, diets, and hunting capabilities. Most of the smaller, more common species of dolphins, such as Bottlenose or Common Dolphins, feed on relatively small prey. The true answer lies in recognizing the one exceptional species in the dolphin family that completely upends the typical predator-prey dynamic.
The Typical Dolphin Diet
The vast majority of dolphin species, including the common Bottlenose and Spinner Dolphins, have diets consisting almost entirely of small fish, squid, and occasionally crustaceans. These species are considered opportunistic feeders that target prey easily caught and swallowed whole.
Physical adaptations explain this dietary preference, as common dolphins possess conical, peg-like teeth that are uniform in shape and are not designed for biting or tearing flesh. These teeth function primarily to grasp and secure slippery, fast-moving prey before it is swallowed headfirst. The average size of a sea lion, which can weigh several hundred pounds, is simply too large, fast, and powerful for a typical dolphin to subdue. Hunting a sea lion would require a specialized tearing and shearing dentition that most dolphins lack.
Orcas: The Apex Predator Exception
The most significant exception to the rule is the Orca, or Killer Whale, which is the largest member of the oceanic dolphin family, Delphinidae. Orcas are apex predators whose immense size—males can reach up to 32 feet and weigh over six tons—and sophisticated hunting strategies enable them to successfully prey on sea lions.
Orca populations exhibit distinct dietary specializations, with one ecotype, known as Transient or Bigg’s Orcas, focusing almost exclusively on marine mammals, including sea lions, seals, and other whales. These mammal-eating Orcas use coordinated pack tactics that are far removed from the fish-herding behaviors of smaller dolphins. They often ram or slap their prey with their powerful tails to stun it before attacking.
Hunting Strategies
One of the most dramatic strategies is “intentional stranding,” where Orcas, particularly in places like Argentina, temporarily beach themselves on steep shorelines to snatch sea lion pups. This high-risk behavior is a culturally transmitted hunting tradition, with adult females actively teaching their young how to time the waves to capture their prey and safely return to the water.
Transient Orcas also hunt larger pinnipeds in the open ocean by working as a group to isolate a sea lion, taking turns ramming it or tossing it into the air to disorient and injure it. Their success in hunting large marine mammals is due to their brute force, intelligence, and highly cooperative social structure.
Interactions and Resource Competition
Outside of the Orca lineage, the relationship between sea lions and typical dolphins is generally one of coexistence and competition rather than predation. Both dolphins and sea lions frequently inhabit the same productive coastal waters because they share a preference for similar food resources, primarily schooling fish and squid. This spatial overlap means they are often competing for the same limited prey base, especially when food resources are patchy or concentrated in specific areas like submarine canyons.
This shared environment often results in mixed-species aggregations where sea lions and dolphins are observed feeding simultaneously. In fact, sea lions have been documented following dolphin schools, seemingly taking advantage of the dolphins’ superior echolocation and herding abilities to locate concentrated pockets of fish. While occasional aggressive encounters might occur due to territoriality or competition over concentrated food, there is no evidence of typical dolphin species actively hunting or consuming adult or juvenile sea lions. The interaction is largely driven by resource dynamics.