Recognized by their distinctive black-and-white patterning and long dorsal fin, orcas, also known as killer whales, are some of the most widely distributed and popular whales of the world. Healthy adult orca whales are at the top of the food chain and are not vulnerable to many predators. When it comes to defenses, orcas rely on echolocation, close-knit social groups, hunting ability, massive size and sharp senses.
Orca whales use echolocation to communicate, hunt and navigate. Echolocation involves the use of sound and its echoes to give a whale a picture of the surrounding area. Echolocation also allows orcas to navigate past obstacles in some of the deepest parts of the ocean. Orca whales also use echolocation to find prey. Orcas can communicate using vocalization calls to keep groups of whales, known as pods, together. By staying together, pods can protect older, ailing or very young orcas from predators. Baby orca whales are particularly vulnerable, so adult females will protect the babies by swimming in close, protective circles around them.
Hunting in Numbers
Staying together in large pods also allows orcas to hunt effectively. This ensures that all members of the pods eat enough to survive and remain healthy. Orca whales use cooperative hunting techniques to hunt prey such as seals. Some researchers have reported that pods of orcas will work together to dislodge ice floes. They use their bodies to create large waves, which wash the seals from safety and into the waiting mouths of the whales. Orcas will also intentionally beach themselves next to seals, grab their prey and drag themselves back into the water with the help of the tides.
Size and Senses
The sheer size of the orca could be one of its best defenses. Male orcas can reach a length of 32 feet, and female orcas can grow as long as 28 feet. The size of the orca whale guarantees its spot at the top of the food chain. In large pods, orcas make formidable predators. Orca whales will also use their powerful tails to stun prey. The orca's sharp eyesight and acute sense of hearing also help the whale navigate through the water, locate prey and avoid danger.
Orca whales are vulnerable to human threats to their health and survival. Fishermen in Alaska see orcas as competitors and kill them. Orca whales retain more man-made toxins in their bodies than polar bears, reflecting how polluted the Arctic Ocean has become. Orcas are also vulnerable to noise pollution, which disrupts their ability to use echolocation. Construction noise and vessel traffic from whale-watching boats and commercial vessels all have the potential to negatively impact the orcas. While these whales may be at the top of the food chain, human beings clearly pose the biggest threat to their well-being.
- NOAA Office of Protected Resources: Killer Whales
- Mammal Review: A Review of Killer Whale Interactions with other Marine Mammals: Predation to Co-Existence
- The Times/Tribune: Food, not Boats, Threat to Orcas
- National Oceanic and Atmospheric Administration Fisheries: National Marine Mammal Laboratory
- Nature News: Unique Orca Hunting Technique Documented
- National Geographic News: Killer Whales are Most Toxic Arctic Animals
Alissa McElreath is a writer and educator based in Raleigh, N.C. She holds an M.A. in creative writing from the University of Binghamton and an M.A. in English literature from the University of Rochester. McElreath's work has been published in "Literary Mama" magazine, on the Family Education Network website and in the anthology "Mama, Ph.D.," published by Rutgers University Press.