Whale Tales

Whale Tales

Short article on blue whales featuring research biologist John Calambokidis.


6 - 12+


Biology, Earth Science, Oceanography, Geography, Geographic Information Systems (GIS), Physical Geography

NGS Resource Carousel Loading Logo
Loading ...

The largest animal that has ever lived, blue whales can grow to 100 feet (30 meters) long, which is longer than the length of a basketball court. They can weigh as much as 200 tons (181 metric tons), about the weight of 15 school buses.

So when a blue whale does an ordinary act that is necessary for its own survival—even just breathing or gliding through the ocean—it can be an awe-inspiring event.

“I think it’s humbling,” says John Calambokidis, a marine mammal research biologist who studies blue whales. “Often, we are working in boats 18 feet long, and these animals we are approaching can be five times larger.”

Calambokidis is co-founder of Cascadia Research, a nonprofit organization based in the U.S. state of Washington that studies marine mammals in an attempt to help protect them. Calambokidis has traveled all over the Pacific Ocean—from off the coast of Costa Rica, where he was funded by expedition grants from the National Geographic Society, to the Queen Charlotte Islands in British Columbia, Canada. He travels to research blue whales. Having observed about 5,000 blue whales in the wild, Calambokidis has witnessed the behaviors of the enormous creatures up close and personal.

The scientist can easily recall the first time he heard the geyser-like explosion of air from a blue whale breathing nearby.

“Here’s this massive animal exhaling virtually all of the air in its lungs in a fraction of a second,” he says. “It comes out with an explosive force. It literally made me jump in the boat.”

Calambokidis says a blue whale’s call, which the animal uses to communicate with other members of its pod and possibly to sonar-navigate the oceans, is a far cry from the sounds emitted by other marine organisms.

“The calls they make underwater are some of the loudest sounds any animal makes,” he says.

But the low-frequency sound is normally below a human’s hearing range. Calambokidis never heard a blue whale’s call during the first decade he was studying the animal. Eventually, with the help of a hydrophone, a microphone that picks up noises underwater, he was able to hear the deep, pulsating sound.

“Hearing that reverberate through was one of the more impressive times I’ve heard an animal call,” he says.

Just as impressive as its call is the noticeable mark a blue whale leaves behind as it sinks into the sea. The phenomenon is called a flukeprint.

“The flukeprint is created by the upward motion of water coming off the trailing edge of the fluke [the whale’s tail] as the animal basically begins its acceleration downward,” Calambokidis says. “So what it ends up looking like is basically an upwelling mass of water that starts as a small circle and spreads outward.”

There is one striking aspect of a blue whale that has nothing to do with the animal’s enormous size—its appearance underwater.

“Especially in the sunlight, when they are traveling just below the surface, they can get this almost shimmering light, an almost turquoise glow,” Calambokidis says. “They can almost seem to glow underwater.”

While blue whales dwarf their adversaries in the sea, the large marine mammals are surprisingly timid, Calambokidis says.

“Their response to killer whales is to flee at high speed,” he says. “People might not expect that from the largest animal that has ever lived.”

Though a blue whale’s tongue can weigh as much as an elephant, the giant ocean creature survives almost exclusively on a diet of two-inch shrimp-like organisms called krill. During certain periods of the year, a blue whale can eat as much as 4 tons of krill in a single day. It then expels the processed food in a defecation trail, which Calambokidis describes as a brick-red cloud that colors the water.

The world population of the docile creatures dwindled severely from 1900 to the mid-1960s, when blue whales were being hunted extensively for whale oil. Whale oil is a substance made from whale’s fat, or blubber. Whale oil can be used as a heating and lighting fluid. It is estimated that 360,000 blue whales were killed during that period. In 1966, the killing of blue whales was banned by the International Whaling Commission.

Scientists believe there are between 10,000 and 25,000 blue whales left in the Earth’s oceans.

Even though whale hunting no longer threatens the endangered species, Calambokidis says there are other dangers facing the blue whale today. Underwater sounds from ships and sonar might affect the animals. Many scientists worry that climate change could alter the whales’ ecosystems. One definite cause of blue whale deaths occurs when large ocean vessels inadvertently strike the marine mammals. In fall 2007, four blue whales were killed by ships off the coast of Southern California.

With Cascadia Research, Calambokidis is trying to learn more about blue whales in an effort to ensure their population doesn’t dwindle any more.

“They do represent one of the more magnificent animals that we have on the planet,” he says.

Fast Fact

Keep it Down, Down There
The blue whale is the loudest animal on Earth. Sound is measured in decibels (db).
70 db: Normal human conversation
140 db: Jet engine
150 db: Outdoor music concert
180 db: Blue whale call
190 db: Some hearing loss

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Stuart Thornton
Jeannie Evers, Emdash Editing, Emdash Editing
Kara West
National Geographic Society
Last Updated

October 19, 2023

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.


If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.


Text on this page is printable and can be used according to our Terms of Service.


Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources