As kids, being able to hold your breath underwater for 10 seconds felt like the ultimate flex.
You and your friends would challenge each other at the pool, seeing who could last the longest, until a teacher, lifeguard, or any sensible adult put a stop to it. But no matter how long you managed to stay under, it’s nothing compared to what this remarkable group can do.
Meet the Bajau, a remote tribe known as the “Sea Nomads,” who can swim underwater for up to five hours a day. Incredible footage has captured their extraordinary ability, leaving many in awe.
While you might assume they have superhuman lung capacity, the real secret lies elsewhere, in their spleens.
The Bajau, who live across Indonesia, Malaysia, and the Philippines, have developed a unique genetic adaptation. Researchers discovered they carry a “mutated gene” known as PDE10A, which is linked to significantly larger spleens. This allows them to store and release more oxygen while diving, enabling them to stay underwater for extended periods and reach astonishing depths.
Melissa Ilardo, a researcher from the University of Copenhagen and one of the study’s authors, explained their way of life to the BBC’s *Inside Science* program:
“For possibly thousands of years, [they] have been living on houseboats, traveling from place to place in the waters of Southeast Asia and visiting land only occasionally. So everything they need, they get from the sea.”
Their incredible adaptation makes them some of the most skilled free divers in the world, proving that, sometimes, evolution can create real-life aquatic superheroes.
“When diving in the traditional way, the Bajau spend around eight hours a day underwater, making repeated dives. Incredibly, they spend nearly 60 percent of their time submerged, with dives ranging from 30 seconds to several minutes, sometimes reaching depths of over 70 meters.”
If you’re wondering how a larger spleen plays a role in this, here’s the science behind it.
When you hold your breath and submerge in water, your body activates the “dive response.” This natural reflex slows your heart rate and constricts blood vessels in your extremities, ensuring that oxygen is preserved for vital organs.
The spleen plays a crucial role in this process. It contracts as part of the dive response, acting like a “biological scuba tank” by releasing oxygen-rich red blood cells into the bloodstream.
Melissa Ilardo, the lead researcher in a study on the Bajau, found that their spleens are about 50 percent larger than those of their land-dwelling neighbors. This genetic advantage allows them to stay underwater for extended periods, making them some of the most remarkable free divers in the world.
However, living so closely connected to the sea has also made the Bajau some of the first to suffer from the devastating effects of climate change and ocean pollution.
Damaged coral reefs and dwindling fish populations have disrupted their way of life, threatening a centuries-old tradition of harvesting the ocean’s bounty. Pollution, particularly plastic waste, has also impacted their culture in unexpected ways.
Santarawi Lalisan, a respected elder of the Bajau, spoke to Giuseppe from Project Happiness about these changes. He expressed concern that Western influences are eroding their traditional ways.
“A lot of plastic has arrived here because today the Bajau go to the supermarket, and here they use plastic instead of paper,” he explained. “In the past, the Bajau only used paper when they were buying something.”
As their environment changes, so too does their way of life, raising questions about how much longer their extraordinary seafaring culture can endure.
