Real Seals Wear Helmets

The northern elephant seal can dive deeper and longer than a sperm whale, stay submerged for up to two hours, and reach depths of more than a mile. Doctors may be able to use the new knowledge of the seal's unusual physiology to develop treatments for heart attacks and strokes in humans

Story by Robert Evans

Illustrated by Alejandro Cruz


Researchers in California, Massachusetts and British Columbia are trying to understand how an elephant seal can dive so long and so deep. They fit the animal with a strong plastic helmet sealed around the neck, and then flood it with water. When that happens, the animal holds its breath, a naturA PICTURE OF AN ELEPHANT SEAL WITH A HELMET reaction to having water on its face, and just as it does in a real dive. The scientists then put the elephant seal into an MRI (Magnetic Resonance Imaging) machine, which can make images of the internal structures of the animal's body. Such machines are used for many diagnoses in hospitals. Pictures of the blood vessels while the animal is "diving" show that blood travels only to organs that need oxygen: brain, heart, muscles. Blood-flow, and therefore oxygen-supply, shuts down to the kidneys and to the body's extremities. The animal's metabolism slows down so that it doesn't need as much oxygen, and what it needs is stored in its spleen and muscles. The seal is one of the world's greatest submarines, and may give us clues to help humans in medical crises.

Please see the full story for more on this amazing pinniped.