The orca, or killer whale, is an intelligent and powerful predator found in every ocean across the globe. As apex predators, they sit at the very top of the marine food chain. Their diets are remarkably diverse and complex, varying significantly depending on their location and social group.
The Apex Predator’s Menu
Globally, orcas have been documented preying on more than 140 different species. A significant portion of their diet can consist of fish, with some populations consuming around 30 different fish species. Common prey includes salmon, herring, cod, and tuna, with specific preferences varying by region.
Beyond fish, many orcas target marine mammals. This includes a wide range of animals such as seals, sea lions, porpoises, and dolphins. They are also known to hunt the calves of large whale species, including gray whales and even the enormous blue whale.
The orca’s diet also extends to other, less common marine animals. They are the only known predators of great white sharks. In addition, some orcas consume rays, sea turtles, and various marine birds like penguins and gulls.
Specialized Diets of Different Orca Types
Scientists classify orcas into distinct groups called ecotypes, based on their specialized diets and hunting patterns. These groups have different social structures, genetics, and vocalizations tied to their specific prey. This specialization leads to unique dietary cultures passed down through generations.
The “Resident” orcas of the Pacific Northwest are fish specialists. Their diet is overwhelmingly composed of salmon, with a particular preference for Chinook salmon. This consistent diet of fish often leads to their teeth becoming worn down over time. Residents live in large, stable family groups and use complex communication to locate and herd fish.
In the same waters, “Bigg’s” or “Transient” killer whales focus exclusively on marine mammals. They hunt in smaller, quieter groups to avoid alerting their prey, which includes seals, sea lions, porpoises, and other whales. Unlike Residents, their teeth remain sharp, an adaptation suited for tearing through the flesh of their prey. The distinction between these two ecotypes highlights how different groups can coexist by targeting entirely different food sources.
A third group known as “Offshore” orcas patrols the outer continental shelf. Their diet is less understood but is believed to consist primarily of sharks, including sleeper sharks and potentially great whites. This diet is thought to be the cause of wear on their teeth.
Cooperative Hunting Strategies
The methods orcas use to capture prey are as varied as their diet and showcase their high intelligence and social coordination. These are not random acts of predation; they are learned behaviors, refined and passed down through generations within a pod. The specific techniques often correspond directly to the type of prey being hunted.
One strategy is “carousel feeding,” used by fish-eating orcas. A pod will work together to herd a school of herring or other fish into a tight, defensive ball close to the surface. Once the fish are densely packed, the orcas will strike the ball with their powerful tail flukes, stunning or killing multiple fish at once, which they then consume.
Another example of teamwork is “wave-washing,” a technique primarily observed in Antarctic waters. Orcas hunting seals resting on ice floes will swim in unison, creating a large, powerful wave that washes over the ice, knocking the seal into the water. This complex, coordinated maneuver requires precise timing and communication among the hunting party.
Some orca populations have developed strategies, such as intentional stranding. In certain coastal areas, orcas will launch themselves onto beaches to grab sea lions or seals near the water’s edge. This behavior is dangerous and requires skill, as the orca risks becoming permanently beached.
Daily Food Requirements
An adult orca can consume up to 5% of its body weight daily, which can translate to as much as 500 pounds (about 227 kilograms) of food. This figure varies based on the animal’s size, age, and the energy content of its prey. This high caloric intake is necessary to fuel their metabolism and the significant energy expended during hunting.