Sea Kids See Clearly Underwater

Sea-gypsy children spend so much time swimming that their eyes have adapted to improve vision underwater.

Mermaids probably don’t exist. But there are children of certain tribes in Asia who are distinctly fishlike.

Called sea gypsies, these island-dwelling people are famous for their swimming and diving skills. A study now shows that sea-gypsy children spend so much time swimming that their eyes have adapted especially well to seeing clearly underwater.

The human eye.

If you’ve ever opened your eyes in a lake without goggles on, you know how hard it can be to find objects or recognize your friends, even at a close distance. That’s because our eyes work best in air.

Sea gypsies, on the other hand, have lived on the islands and in the waters of Southeast Asia for hundreds of years. From a young age, they learn to swim and dive. Sea-gypsy children have an amazing ability to find morsels of food underwater.

To understand how they do it, Swedish researcher Anna Gislen studied the Moken people off the west coasts of Burma and Thailand.

In eye exams, 6 Moken children were far better at focusing their eyes and picking out objects underwater than 28 European kids who did the same tests. In both groups, however, underwater vision remained imperfect compared with their above-water eyesight.

The researchers think anyone’s eyes could get better at seeing underwater with just a few months of practice. Even then, though, the chances of seeing a mermaid underwater would be pretty slim!—E. Sohn

Going Deeper:

Travis, John. 2003. Gypsy secret: Children of the sea see clearly underwater. Science News 163(May 10):308-309. Available at http://www.sciencenews.org/20030517/fob4.asp .

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