Orcas, often called “killer whales,” are apex predators found in every ocean. These marine mammals, the largest members of the dolphin family, are recognized for their distinctive black and white markings. Their reputation as hunters stems from highly organized social structures and diverse predatory behaviors. Orcas occupy the top of the food web, adapting their hunting strategies to a wide array of prey and thriving in various marine environments.
Specialized Orca Diets
Orcas comprise distinct populations known as ecotypes, each with specialized diets and behaviors. Transient orcas, also called Bigg’s killer whales, primarily hunt marine mammals, contrasting with Resident orcas that mostly consume fish like salmon. Transient orcas have evolved specific hunting techniques and social structures suited to pursuing seals, sea lions, porpoises, dolphins, and other whales. These behavioral adaptations support their mammal-hunting lifestyle.
They are notably quieter than fish-eating ecotypes, communicating less frequently while hunting to avoid alerting prey with acute hearing. This stealthy approach allows them to surprise unsuspecting marine mammals. Their movements are also less predictable, covering wide ranges to search for their mobile prey.
Common Whale Prey
Transient orcas prey on various whale species, with calves being particularly vulnerable. Gray whale calves, for instance, are commonly attacked during migration. These young whales, often traveling close to shore with their mothers, become accessible prey for opportunistic orca pods. Minke whales are another species frequently hunted by Transient orcas.
Orcas also occasionally target larger whale species, such as humpback whales, especially their calves or individuals that are sick or weakened. The size and health of the prey influence its susceptibility, leading orcas to often single out the young, old, or infirm within a group.
Hunting Strategies
Orcas display intelligence and coordination in their hunting efforts, working together in pods to overpower large prey. Their strategies involve isolating, exhausting, and incapacitating whales. Orcas may ram and bite prey, focusing on vulnerable areas to wear down the animal. They target a whale’s pectoral fins or try to prevent it from reaching the surface to breathe.
Cooperative hunting allows orcas to tackle animals significantly larger than themselves. They use sophisticated communication, including specialized vocalizations and silent coordination, to execute complex maneuvers. A well-documented technique for marine mammals, “wave-washing,” involves multiple orcas creating a large wave to dislodge prey from ice floes. The goal of these coordinated attacks is to drown prey by preventing it from surfacing for air.