Killer whales, also known as orcas, are highly intelligent and adaptable apex predators found in marine environments across the globe. These powerful marine mammals are at the top of the food chain. A common question arises about their diet: do killer whales eat seals? Yes, seals are a significant prey item for certain killer whale populations. Their intelligence and sophisticated hunting techniques allow them to successfully target a diverse range of prey, including seals.
Specialized Hunting Strategies
Killer whales, particularly the mammal-eating ecotypes, employ specialized and coordinated hunting strategies to catch seals. These intelligent predators often work together in groups. One well-known technique in icy environments involves “wave-washing,” where several killer whales will create a large wave to wash a seal off an ice floe and into the water. Once the seal is in the water, other killer whales are often waiting to intercept it.
Beyond wave-washing, killer whales also use direct tactics such as ramming or tail slapping to incapacitate their prey. They might throw seals into the air or slap them with their tails. In some regions, like the steeply banked beaches of Península Valdés, Argentina, killer whales even temporarily beach themselves to snatch seal pups and adult elephant seals from the shore. Common seal prey includes harbor seals, grey seals, and elephant seals.
Dietary Diversity Among Killer Whale Populations
While some killer whales actively hunt seals, not all populations have the same diet. Killer whales exhibit distinct “ecotypes,” which are populations with specialized diets and hunting behaviors. The primary ecotypes in the North Pacific are “transient” (or Bigg’s) killer whales, “resident” killer whales, and “offshore” killer whales. Transient killer whales primarily prey on marine mammals, including seals, sea lions, porpoises, and even other whale species. These mammal-eating transients often hunt silently to avoid detection.
In contrast, resident killer whales primarily consume fish, with some populations, like the Southern Residents, relying heavily on salmon, especially Chinook salmon. Resident killer whales are more vocal because fish are less sensitive to their calls. Offshore killer whales have a diet that includes fish and sharks. Their teeth often show significant wear from preying on rough-skinned sharks.
Apex Predator Dynamics
Killer whales occupy the top of the marine food web as apex predators. Their position allows them to influence marine ecosystems by regulating the populations of their prey. Predation on seals by killer whales contributes to natural selection, as weaker or less agile individuals are more likely to be caught. This process can help maintain the health of seal populations.
The impact of killer whale predation on seal populations has been observed in various regions. Declines in sea lion and fur seal populations in the North Pacific during the 1960s and 1970s were linked to increased killer whale predation. Similarly, killer whales have been linked to declines in southern sea lion and southern elephant seal numbers in the Antarctic. By consuming various marine species, killer whales play a role in the balance of oceanic life.