10 top questions about Orca

11-Nov-2021

We’ve compiled the following list of questions about killer whales that we frequently get asked.

1. 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! Orca killer whales are divided into separate populations, each with its own geographical range, physical variations, diet, language and social structure—otherwise known as culture!

2. Why are they called killer whales?

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.

Karac Lindsay Photography / Eagle Wing Tours

3. 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!

4. How big are killer whales?

Killer whales are actually the largest member of the dolphin family! Of the three killer whale ecotypes 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!

Valerie Shore Photography / Eagle Wing Tours

5. How deep do killer whales dive?

Typical dives are less than 300 metres and last about four minutes. Some dives can be as long as 20 minutes. But killer whales can descend further and longer when food-motivated. The world record-holder is an adult female in the southern Atlantic Ocean where killer whales steal fish off the longlines of the Patagonian toothfish fleet. This particular female dove to an astonishing depth of 1,087 metres! This depth is pushing their physiology to the extreme, note researchers, as one whale spent four hours recovering at the surface!

6. How long do killer whales live?

In some ways, their life cycle is similar to that of humans. Males reach maturity at around 15 years of age and continue to grow until they’re about 20. Although their average life expectancy is just over 30, they can live as long as 60. Females can have their first calf at around age 12-14. In healthy times, a female might have a calf every 3-5 years until she’s about 40. But she can live for decades after that—to 80 years old or more. Female killer whales have the longest non-reproductive lifespan (menopause) of all animals besides humans!

Karac Lindsay Photography / Eagle Wing Tours

7. Why are killer whales black and white?

Notice how they’re black on top and white below. This is known as countershading and we see it in many other animals too. Countershading is a form of camouflage to either avoid being eaten or avoid being seen by something you want to eat! For killer whales, it makes them less visible to prey from both above and below. Also, that swirly black-and-white pattern helps break up the outline of their large bodies, further confusing their prey!

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!

Valerie Shore Photography / Eagle Wing Tours

9. How many teeth do killer whales have?

They have 20-28 conical teeth on their upper and lower jaws, each 3-4 inches long. They interlock like those of a Tyrannosaurus rex! They don’t chew their food. They use those pointy teeth to grasp their food and tear it into pieces. Killer whales need to eat 5% of their body weight every day! Globally, the menu includes just about every large mammal species that lives in the sea, plus various types of fish, squid, turtles and birds such as penguins! But a lot depends on where a killer whale lives and what its mother taught it to eat. Here in the Salish Sea, the fish-eating southern residents are chinook salmon specialists while Bigg’s killer whales are marine mammal hunters!

10. How smart are killer whales?

They have the second largest brains among all ocean mammals (the sperm whale is the biggest) so that’s a clue. It weighs in at about 15 lbs. Sure, bigger animals typically have bigger masses of brain cells. Looking solely at brain weight-to-body weight ratio as a measure of intelligence, killer whale brains are 2.5 times average, similar to those of chimpanzees. But there’s more going on in those big heads. Their brains have more convolutions and surface area than ours, suggesting a heightened ability to process information and emotions. These are very complex social and emotional animals. And they’re smart, probably much smarter than we think!

Blog written by Eagle Wing Tours naturalist Valerie Shore

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