5 Surprising Facts About Orcas

orca in front of white and blue boat surrounded by birds

Alessandro De Maddalena / Shutterstock

The orca is one of the most ferocious animals out there. Easily identified because of its black and white pattern, it is often used as playful marine imagery. However, it's been dubbed as a killer whale for a reason; they are apex predators, meaning they are top of the food chain.

These social animals are known for a lot of things, from their appearance to their social practice of traveling in pods. There's more to these exciting creatures though, so here are eight lesser-known facts about orcas.

1. Orcas Aren't Whales

Orcas are often called killer whales — they certainly have the size to be listed among those massive creatures. However, orcas are not actually whales; they are dolphins (and the largest species of dolphin, at that). Taxonomically, they fall into the Delphinidae family, which are oceanic dolphins.

It is theorized that the misnomer was originated by sailors who saw orcas' ferocious hunting of large marine animals and dubbed them "whale killers." Then, the term somehow got flipped around over time.

2. They Have Evolved Based on Culture

Research conducted by Andrew Foote, a killer whale genetics expert, found that orcas and humans share an ability for culture-based evolution. In a 2016 study, Foote and a team of researchers analyzed the genes of different orca pods and discovered that distinctions in genes coincided with distinctions in culture.

One of the most apparent examples of this was in the orcas' hunting behavior — different groups will hunt different types of prey using different techniques. Eventually, those distinctions result in differences in genomes, meaning cultural groups become genetically distinct.

Before this discovery, humans were the only known animals to evolve based on culture.

3. They Go Through Menopause

mother and orca calf jumping out of water together amid mist
Mike Charest / Flickr / CC BY 2.0

Almost all animals in the animal kingdom maintain the ability to reproduce until their deaths. Five species are exceptions to this, including the orca.

Why would a species evolve to stop producing mid-life? For the orca, it has to do with their social practice of staying in pods. Because both sons and daughters remain in the pod throughout adulthood, older females are increasingly related to everyone in the pod. Sharing genes with so many pod members is a good reason to stop breeding and instead focus on supporting the pod by guiding and teaching the children, grandchildren, and great-grandchildren.

4. Orca Clans Speak Different Languages

pod of orca whales jumping from ocean in front of mountains
Ron Sanford / Getty Images 

Orcas stick to pods or family groups, which then join together to comprise a clan. One of the ways clans and pods are distinct from others is their language.

Clans "speak" completely different languages. These large groups coming together would be like trying to have a conversation between an English speaker, a Russian speaker, and a Chinese speaker.

While the pods that make up each clan all speak the same language, they each have a distinct "dialect." It's much like how English speakers in America could have a Southern, New England, and Midwestern accents.

5. They Are Widespread

After humans, orcas are the most widespread mammal in the animal kingdom. The species ranges from the Arctic to the Antarctic and are found everywhere from the freezing waters or the north and south to the warm waters along the equator, including the Hawaiian Islands, Galapagos Islands, and the Gulf of California.

Not only have orcas been seen in all of the world's oceans, but they have also been spotted in freshwater rivers. One even swam more than 100 miles up the Columbia River in Oregon as it hunted fish.

6. Orcas Cannot Smell

Orcas do not have an olfactory system, which means they likely have do not have a sense of smell. While this may seem like a handicap, it actually makes a lot of sense. Unlike sharks, which use smell to track down prey, the orca uses its keen hearing to practice echolocation — producing sounds and listening for echoes to tell if there are objects or animals in their surroundings.

The absence of this smelling system is present in all dolphins, as well as most toothed whales, so orcas are not alone in this deficiency.

7. They Have Big Brains

Orcas have the second-largest brains of any marine mammal, second only to sperm whales. They can weight as much as 15 pounds.

Scientists use brain size — specifically the ratio between brain weight and body weight — to roughly measure intelligence. By that measure, the orca's brain size is 2.5 times larger than the average of other animals. However, because of orcas' impressive social, language, and echolocation abilities, it is believed that their intelligence far surpasses what their brain size suggests.

8. Orcas Scare White Sharks

great white shark swims with mouth open toward camera
Stephen Frink / Getty Images

When orcas and white sharks confront one another, it is the white shark that flees. Research conducted at the Monterey Bay Aquarium in California followed a group of white sharks for several months. These sharks always fed in the same place, but when two pods of orcas arrived, the sharks fled and did not return for months.

It is possible that orcas are targeting white sharks. Another theory is simply that orcas bully white sharks away from prey in the area. Either way, even if orcas are just passing through, white sharks will not return to a location, no matter how well-loved, for up to a year.