In celebration of World Orca Day (which to us is every day!) on July 14, here are 10 questions about killer whales that we often get asked on our tours.

Test your knowledge of the ocean’s top predator!

1. What is an orca?

Orca is another word for killer whale. It comes from the whale’s scientific Latin name, Orcinus orca, which translates into “belonging to the kingdom of the dead.” Some people choose to use “orca,” arguing that “killer whale” sounds too evil. The killer whale camp—which includes most scientists—prefers to call them what they are. It’s an ongoing and lively debate!

2. Why are they called killer whales?

Well, because they are. As the top ocean predator, they kill other animals to make a living, although diets vary among different populations around the world. When mariners travelling the seas hundreds of years ago saw them preying on large whales (as some populations do), they labelled them in their language as “whale killers.” Over time, that got flipped to killer whales.

 3. How many killer whales are there in the world?

There are an estimated 50,000 or more around the world. Next to humans, they’re one of the most widespread mammals on the planet! Globally, killer whales are divided into separate populations, each with its own geographical range, physical variations, diet, language and social structure—otherwise known as culture!

4. How big are killer whales?

Killer whales are the largest member of the dolphin family! Of the three killer whale types of killer whale that we see off BC, the largest are the mammal-eating Bigg’s. Males are bigger than females, sometimes by as much as 30%. Bigg’s males can tip the scales at more than 6,600 kg or seven tons—the weight of about four cars! For all you dinosaur fans, that’s close to the estimated weight of a Tyrannosaurus rex!

5. Why are BC killer whales called residents and transients

The two ecotypes got their name from the early days of killer whale research on this coast. Researchers noticed two very different types. One type travelled in large groups and was seen predictably at certain times of the year—following the salmon, as it turned out. They were designated “residents.” The other type roamed in smaller groups and kept to themselves. They were thought to be social outcasts in transit to other locations—ergo “transients.” We now know the two ecotypes are very different—but the terms resident and transient stuck!

6. What are Bigg’s killer whales?

Bigg’s is the more current term we use for transients. This honours the memory of Canadian biologist Michael Bigg who pioneered a way to identify individual killer whales by their dorsal fins and the grey saddle patches behind the dorsal fin. His work informed an end to killer whale captures, helped transform public attitudes toward killer whales, and launched field studies that continue to this day.

7. Why do killer whale dorsal fins sometimes flop over?

Dorsal fins can be up to 1.8 metres in males—half the height in females—yet they don’t have any bone in them. They’re made up of dense connective tissue called collagen. The water column usually does a fine job of keeping a fin upright. But if you’re a captive killer whale confined to a tank, you spend an unnatural amount of time at the surface. Gravity takes over and the fin often collapses. The rare cases of buckled or collapsed fins in the wild are due to injury, entanglement, genetic deformity, illness, nutritional stress or even age!

8. How do killer whales sleep?

Just like us, they need their rest. But while we breathe automatically when we enter our “unconscious” sleep, killer whales are “conscious breathers.” They have to think about each breath they take. So how do they rest without drowning? Research shows that half of the brain “shuts down,” while the other half remains active to regulate breathing and stay aware of their surroundings. They can even alternate which side of their brain is sleeping!

9. Why are baby killer whales black and orange?

Scientists believe it’s due to a thin blubber layer. When a calf is born, that blubber layer is only about 2 cm thick making the blood vessels more visible. Drinking mom’s milk—which is up to 40% fat— soon changes that. By the time they’re a year old, the orange hue of babyhood has usually disappeared!

10. Why do killer whales breach?

Only the whale knows for sure, but we have a few theories. It may be sending a message to other whales nearby because the splash landing makes a lot of noise underwater. It could be taking a quick look around, or playing. Or in the case of Bigg’s killer whales, celebrating a successful hunt. Or maybe—and this is our favourite theory—it’s breaching because it can and it’s fun!

Come out and see for yourself!

To book a tour and perhaps meet a killer whale in person, give us a call or book online!

Blog written by Eagle Wing naturalist Valerie Shore

Republished July 13, 2022