Killer whales, also known as orcas, aren't whales at all. They're really dolphins, and they're the largest mammal-hunting creatures on earth. Adapting over many millions of years, orcas have physical characteristics and behavioral traits that combined give them several predatory hunting advantages. Apex predators of the sea, killer whales fear no natural predators; the only animals known to hunt them are humans.
Two Types of Pod
Generally, killer whales tend to live and hunt in pods of around 40 individuals. Two types of pod exist, each with specific prey preferences and practices. According to the Marine Science website, large killer-whale pods that return to the same coasts every summer are known as resident pods, and these whales primarily feed on fish, rarely seeking mammalian prey. Resident pods are generally rather passive; they do significantly less hunting than their transient pod counterparts, whose diet is composed almost exclusively of fatty mammals. These smaller transient pods rarely return to the same place, and they actively employ coy hunting strategies to capture favorite foods such as seals, porpoises, walruses, sea lions and dolphins.
Bodies Designed for Hunting
Killer whales are the submarines of the mammal kingdom, perfectly designed for hunting prey at sea. With large, tapered heads and substantial, incredibly powerful tails coupled with their ability to propel themselves through the water at speeds as fast as 35 miles per hour, killer whales have been known to ram their prey or slap them with their tales, rendering the prey unconscious long enough for the whales to consume it.
Killer Whale Coloring
Typically black on top with white undersides, killer whales have adopted distinctive markings to camouflage them from potential prey. Known as counter-shading, this is a common color scheme for aquatic predators. The SeaWorld website puts it this way: “The dark side blends in with the murky ocean depths when viewed from above. The light ventral side blends in with lighter surface of the sea when seen from below. The result is that prey have a difficult time seeing a contrast between the counter-shaded animal and the environment.” Orcas also have large white eyespots that sit just behind and above each eye. They provide a color disruption than can both confuse prey and disguise the location of their real eyes.
Killer Whale Teeth
Killer whales have massive 3-inch teeth lining the length of both jaws, but they're cone-shaped and not terribly sharp. Killer whales have between 40 and 56 interlocking teeth that help to hold prey and to rip or tear flesh, but they do not chew their meals. In fact, according to the "National Geographic" magazine website, these whales either consume their prey in chunks or entirely intact.
Echolocation and Cooperative Hunting
All killer whales use echolocation to communicate as well as to locate food sources, which makes cooperative hunting among members of a pod a successful means of capturing prey. Echolocation allows orcas to bounce sound off objects in order to locate their positions, and they can even produce high-pitched clicking sounds that stun their prey. Killer whales often work together to force fish into restricted areas so each whale can take turns feeding, but they may also collaborate to wash a seal off an ice float -- or one individual whale may temporarily beach himself to frighten penguins or seals into the water, where the rest of the orca pod is hungrily waiting.