Saturday, February 24, 2007

Apple #227: Orcas

The other night, I was out with some friends. The TVs in the bar were playing, for some reason, the National Geographic Channel, which was showing an episode about sharks and other sea animals.

Then one friend -- I'll call him Harvey -- pointed to the TV and said, "Orcas! I hate orcas! They scare me. They're like sharks but smarter, and they're huge -- one orca is as big as this bar." We regarded the TV and him with some skepticism.

Harvey went on, "I just know, someday, I'm going to be on my honeymoon, and we're going to be walking on the beach, hand in hand all nice. Then an orca will swim up onto the beach, slide right up there, and chomp me and carry me out to sea, and I'm going to be like, 'Dammit! I liked her.'"

Well. Clearly, some of what he said was in jest. But is it true that orcas are "like sharks but smarter?" Are they really that big, and will they swim up onto a beach to attack a human?

Orcas seen from the coast of Orcas Island in Washington
(Photo from Orcas Island Bayside Cottages, where you can rent a cottage for about $200 per night)

  • Orcas are also called killer whales. That name "killer whales" is a misnomer, though, first of all, because they are not whales.
  • Orcas are actually part of the dolphin family, and are the largest type of dolphin.
  • They surface and breathe through a blowhole the way dolphins do, and they also communicate with series of complex clicking and chattering sounds. They recognize each other by their sounds.
  • People have also identified distinct populations of orcas, mainly by the "dialects" they use. Orcas from different populations will not inter-breed.
  • Orcas stay with their mothers their entire lives.
  • Orcas live in every ocean in the world, though the highest numbers of orcas live in colder waters. They will sometimes swim into estuaries to catch sea lions and penguins, but they usually don't stray far from the sea. So an orca is not likely to swim up onto a beach to catch something.

The darker blue patches are the places where orcas live.
(Image from

  • Orcas grow to be about 27 to 33 feet long, and they weigh somewhere around 8,000 to 12,000 pounds. For the sake of comparison, large male Asian Elephants weigh around 12,000 pounds, but they're only 11 feet tall.
  • The black on their backs means that animals above the water have trouble distinguishing them from the water's surface. The orcas' white bellies blend in with the light above the surface of the water, so animals in the water have trouble seeing them as well.
  • Orcas eat fish, turtles, squid, octopi, birds, penguins, seals -- and sharks. They have also been known to attack small blue whales. In fact, orcas are at the top of the ocean food chain.
  • A typical orca will eat about 550 pounds of food per day.
  • They are pretty serious hunters. They can achieve bursts of speed up to 30 mph to catch prey. They can dive as deep as 100 feet to go after something.
  • Orcas' teeth are large and interlocked for added stability in the jaw. The teeth curve inwards and backwards in pairs on both the top and bottom of their jaw. Basically, this means they can gnash the flesh of their prey extremely quickly. They don't have to chew their food after the initial strikes, but can swallow animals as large as sea lions whole.

Keiko, getting his teeth checked by a trainer. Each tooth looks about as big around as one of the man's fingers. Supposedly an orca's tongue feels like sandpaper.
(Photo from jikido-san's Flickr photostream)

  • Often orcas will work in groups -- called pods -- to catch their prey. Their tendency to hunt in packs has earned them the epithet "wolves of the sea."
  • Some of their hunting techniques include:
    • Ramming into an ice floe to knock an unsuspecting seal into the water,
    • Slapping their tails on the surface of the water to create a wave that sloshes penguins or sea lions into the water,
    • Herding schools of fish until they are surrounded by orcas and are easily swallowed by the mouthful,
    • Working together in groups to chase larger prey like sharks and biting and chasing the prey until it's too tired and becomes food.
  • The orcas share what they've caught.
  • As far as whether orcas will attack humans, only a very few instances of orcas attacking humans have been recorded. One recent attack happened in captivity, at a Sea World, when an orca carried and repeatedly plunged its trainer underwater. Some people believe that instead of trying to drown the man, the orca was actually trying to breed with him. The orca is such an efficient hunter that if the orca had wanted to eat the trainer, it would have done so without hesitation.
  • update: in February 2010, just after his noontime show at Sea World, an orca named Tilikum surfaced, grabbed one of his trainers by her pony tail and began thrashing her about in the water, eventually killing her.  One dolphin trainer who had warned Sea World that they were working their show mammals too hard said of the incident, "Happy animals don't kill their trainers."  Many trainers and people who work with water mammals say that too many years spent in a tank that's far smaller than their usual habitat makes them "demented."

Here is Shamu being fed -- rewarded -- in captivity. Very different from the way orcas usually eat in the wild. Perhaps this is why some captive orcas, over time, get confused.
(Photo from Scandblue's Flickr photostream)

  • The few attacks on humans that are on record all occurred in captivity, and they are very similar to the Sea World incident.
  • There are no recorded incidents of orcas in the wild attacking humans. This may be because humans tend not to be in the places where orcas hunt.
  • Because there have been so few attacks on humans, people say that orcas should not be called "killer" anything. And once again, orcas are not whales, but dolphins.

So, yes, orcas really are that big. Imagine an animal the size of an elephant, but longer, swimming and eating in the ocean.

And yes, orcas are really that smart. They communicate using a distinct form of language, and they have developed sophisticated hunting techniques. So yes, they are "like sharks but smarter." In fact, they eat sharks.

However, since orcas prefer to stay in the ocean, they will not steam up onto a beach. Unless a human being is a trainer putting him or herself near the mouth of an orca on a regular basis, it is very unlikely an orca will attack a person. So unless Harvey is planning on honeymooning on the beaches of Antarctica and masquerading as a sea lion at the edge of an ice floe, he is probably safe from the orcas.

Enchanted Learning, Orca
National Geographic for Kids, Orcas Fun Facts
Orca Network
PetsandWildlife, Largest Dolphin: Orca (Killer Whale) Fact Sheet
Tigerhomes, Killer Whale Attacks on Humans - Orca Attacks
Humane Society of the United States, Sea World Attack Reaffirms Whale of a Truth
Singapore Science Centre, Do killer whales attack humans?

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