Snorkeling Elephants and the Secrets of Breathing

<< Back to Page 1   Page 2 of 2

Since then, the big question has been why. Does it have anything to do with the elephant's snorkeling ability, and is it the result of evolution?

In all other mammals, the lungs are surrounded by two layers of a thin membrane called the pleural cavity. Imagine a double-bagged garbage can: The can is the ribs, the trash is the lung, and the space between the two bags is the pleural cavity. In humans and other mammals, there's about a teaspoon of liquid between the two layers.

In elephants, the pleural cavity is filled with connective tissue. "It's not muscle and it's not meat—it's slippery-slidey kind of stuff that allows bits to slide over each other," said West.

"No other mammal," he pointed out, "has that anatomy."

The unusual lung structure enables elephants to withstand the extreme differences in pressure above and below water without rupturing blood vessels in the lining of the lungs.

Genetic evidence suggests that the elephant's closest relatives in evolutionary terms are manatees and dugongs, herbivorous sea cows that live full-time in the water. For some reason—the availability of a food source that no other creature was exploiting is one possibility—elephants, over time, developed legs that were strong enough to support their huge body weight and enabled them to become land creatures.

West suggests that elephants also evolved trunks so they could breathe with their heads underwater.

To this day, elephants remain powerful swimmers.

Astronomers, Climbers, and Miners

What about mountain climbers in the Himalaya, astronomers, and miners in Chile? They all work at high altitudes, breathing "skinny" air.

At sea level, air contains about 21 percent oxygen. The pressure decreases as altitude increases; at 12,000 feet (3,658 meters) there are roughly 40 percent fewer oxygen molecules per breath.

To deal with the lower oxygen content, people at high altitudes start breathing much faster, even while resting. One climber likens it to running on a treadmill while breathing through a straw. Breathing thinner air has lots of potential consequences, none of them good.

Symptoms range from headache, loss of appetite, and insomnia to delusional thinking, loss of coordination, and life-threatening medical conditions known as high-altitude pulmonary edema and high-altitude cerebral edema.

"We're working on developing a new technique of oxygen enrichment of room air to allow people to work in conditions where otherwise they'd be hopelessly inefficient," said West.

"Really it's for commuters from sea level to high altitudes, like astronomers, who have to be as high up in the world as they can get," he explained.

The technique could also prove useful at ski resorts.

"There is one resort in Cuzco, Peru, which is a little over 11,000 feet, where they're using it," said West. "The problem with Cuzco is that everybody comes in straight from sea level. They fly in from Lima, and they're immediately at this quite high altitude, and they have a lot of problems with it."

For West, there is no end to the fascinating things a scientist can discover.

"The excitement of science," he said, "is that if you're curious, there are very interesting things you can unearth."

Bookmark this page for National Geographic News stories updated daily: Go>>

Related Stories from Nationalgeographic.com:
Ivory Trade Ban May Be Overturned This Month
Pheromone in Urine Spurs Mating in Elephants
"Elephant Excess" NGM photo gallery
Elephants May "Talk" Via Vibrations
Painting Elephants Get Online Gallery (with photo gallery)
Opinion: How Do You Miss a Whole Elephant Species?
Elephants Airlifted to Repopulate War-Torn Park in Angola
DNA Tests Show African Elephants Are Two Species

Join the National Geographic Society

Join the world's largest nonprofit scientific and educational organization, and help further our mission to increase and diffuse knowledge of the world and all that is in it. Membership dues are used to fund exploration and educational projects and members also receive 12 annual issues of the Society's official journal, National Geographic. Click here for details of our latest subscription offer: Go>>

<< Back to Page 1   Page 2 of 2


SOURCES AND RELATED WEB SITES

ADVERTISEMENT

NATIONAL GEOGRAPHIC'S PHOTO OF THE DAY

NEWS FEEDS     After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.   After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

National Geographic Daily News To-Go

Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.
Click here to get 12 months of National Geographic Magazine for $15.