Swimming with Sharks

Would you let your kids keep a pet shark? You would if you were part of the Bajau tribe, where children learn to swim before they can walk and spear fish at age 8. The Bajau are sea nomads in Indonesia, the Philippines, and Malaysia, who live on boats and follow fish populations. Traditionally, they come ashore only to trade their catch and escape storms. To make their living diving for fish, the Bajau have adapted to do things the rest of us can’t. In fact, they’ve developed some of the same capabilities as seals and whales. When they dive, their bodies direct blood away from their extremities and toward their brain and organs. Most importantly, they’ve developed 50 percent larger spleens, which act like an oxygen reserve, storing and then releasing more red blood cells into their systems when they dive. All Bajau, even those who don’t dive, have an enlarged spleen, indicating it’s genetic. With these adaptations, most Bajau can spend 5 hours a day underwater. They dive easily to 60 ft and stay there for minutes at a time! They can go to depths over 200 ft with nothing more than wooden goggles and weight belts to pull them to the bottom. Then surface and do it again. Western scientists are studying the Bajau to see how they can thrive with less oxygen—a condition called hypoxia, which can cause free divers to lose consciousness and drown. Perhaps the secrets of the Bajau will save lives elsewhere.