The nomadic Bajau Laut of Southeast Asia live a remarkable life. The seafaring community live on the ocean, trading and fishing, spending up to 60% of their working lives in the water. Their free-diving abilities are impressive, with the deepest dive ever recorded was for three minutes at a depth of 79 metres. New research published in the journal Cell shows that they have some physical and genetic adaptations to help them make these amazing dives. Using only a pair of carefully crafted wooden goggles and some metal hand weights they brave the depths of the ocean to find fish. When you free-dive, you can a huge gulp of air, pull your head under the water, and swim down to the ocean floor without assistance.
It requires a massive amount of work from your heart and lungs, but your spleen is important too because it stores a reserve of red blood cells. When you are free-diving, your spleen jumps into action by contracting and squeezing out the extra blood cells to increase the capacity to carry oxygen. But an international team of researchers studying the Bajau have found physiological differences in their genetics that suggest they have adapted to their life at sea. The discovery that the people of Bajau Laut have larger spleens, even those who don’t dive, suggests that this is an inherited trait that allows them to dive for longer. Other genes were discovered too, including one responsible for causing blood to be squeezed out of the extremities so that the body can focus on providing oxygen to the brain, heart, and lungs, and another gene that stops high levels of carbon dioxide from building up in the blood. The findings are incredible and suggest that the community have evolved to become more adapted and efficient at life at sea, more than any other people on our planet.
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