These Whales are Killer!

(except they aren’t really whales)

Although orcas are commonly referred to as “killer whales”, orcas are actually dolphins! The orca’s nickname is attributed to its ability to attack large marine animals such as whales! As apex predators, orcas have earned their right to be called “killer”. Orcas are very large, weighing up to 6 tons and growing as long as 23 to 32 feet!

Physical Appearance

Through adaptation, orcas’ bodies are black and white, assisting them in their hunt for food; the outline of their color change camouflages them to sea life below the surface. Killer whales have humongous teeth for hunting; they can grow up to 4 inches long! The orca’s dorsal fin (the fin on their back) is also very large, and their body’s cylindrical shape that narrows at its ends allows for great aerodynamics!

An orca up close, showing off its long, sharp teeth.

Predator and Prey

Besides humans, no marine animals hunt killer whales. Killer whales, on the other hand, hunt and consume almost every marine mammal that we know exists. They also will eat many other marine animals, such as birds, sharks, fish, and cephalopods (octopus/squid). One of the orca’s hunting techniques involves waiting in shallow water and jumping onto land to prey upon seals on the shore.

The Orca’s Grand Domain

Surprisingly, orcas are the most interspersed mammal species (other than humans), residing in all of Earth’s oceans! Orcas typically travel and do not stay in one place, and they are able to adapt to a multitude of climates! Although they are spread out across all of our oceans, they are more likely to be found in the northern hemisphere, by land.

Echolocation and Communication

Similar to whales and other dolphins, killer whales use echolocation. The killer whale creates a sound (wave) which reflects off of life and/or objects. The sound wave returns to the orca and lets it know what life or objects are in the area (as well as their shapes and sizes)! This ability makes hunting much easier as well as communication with other orcas. Different pods and families of orcas have unique ways of communicating with one another, allowing for information to be passed down through the generations.


Killer whales have a very interesting form of “sleep”, known as unihemispheric sleep. Unlike humans, killer whales cannot breathe in an unconscious state, so they are forced to remain conscious while they are sleeping by leaving half of their brain turned on. Since each side of the brain controls the opposite side of the body, killer whales sleep with one eye closed, and one eye open (corresponding to whichever halves of the brain are asleep and awake). To get even rest on both sides of the body, orcas periodically alternate which side of their brain/body is asleep.


The population of orcas/killer whales is unknown, but there are multiple protected populations, just to be safe. Like other marine life, human interactions with the environment as well as human fishing and hunting pose serious threats to the future of the killer whale.

Fun Facts

Nickname: Orcas were initially known as “whale killers”, until the name naturally switched to the better sounding: “killer whale”!

Social Life: Killer whales are very social! Many live in pods (groups) of up to 40; they work together to hunt their next meals!

Reproduction: Orcas take a long time to reproduce, with each female only being able to give birth to one calf once every 3 to 10 years

Prey: According to Sea World, orcas also eat moose!



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