Imagine being able to dive to the ocean floor without an oxygen tank, holding your breath for minutes at a time, and hunting fish like a real-life Aquaman. Sounds impossible, right? Well, for one group of people, it’s just another day at the office.
Meet the Bajau, Southeast Asia’s legendary sea nomads. For centuries, they’ve lived on the water, diving to staggering depths, and surviving in a way that seems almost superhuman. Their secret? Science now suggests they’re really are built differently from the rest of us in some astounding ways.
Meet real Human Mermaids, as we dive into the world of the Bajau, a people who might just be the closest thing we have to aquatic superhumans.
For most of us, the ocean is a place of mystery, beauty, and maybe even a little fear. But for the Bajau, it’s home.
Often called the “Sea Nomads,” the Bajau have spent hundreds of years drifting between the coasts of Indonesia, Malaysia, and the Philippines. They live on houseboats or stilted homes built over the water, only occasionally stepping foot on land. Their entire way of life is built around the sea—fishing, diving, and harvesting resources from the ocean floor. And they do it all without any modern diving equipment. No wetsuits. No oxygen tanks. Just a pair of handmade wooden goggles, a simple spear, and lungs that seem to defy human limits.
So, what makes them so different from the rest of us? It turns out, the answer is hidden deep inside their bodies. And the Secret Lies in the Spleen…
Most people don’t think about their spleen—it’s just one of those organs we tend to forget even exists. But for the Bajau, it’s a game-changer.
When any human submerges in water, a natural reflex called the diving response kicks in. Your heart rate slows down, your blood vessels constrict, and your spleen contracts, releasing oxygen-rich red blood cells into your system. It’s your body’s way of conserving oxygen and extending the time you can survive underwater.
But, here’s where things get interesting. A 2018 study found that the Bajau have spleens that are 50% larger than those of their land-dwelling neighbours, the Saluan people. A bigger spleen means more stored oxygen, which allows them to hold their breath far longer than the average human. And here’s the kicker—it’s genetic.
Scientists discovered that the Bajau carry a unique mutation of the PDE10A gene, which controls spleen size. This same kind of adaptation has been observed in diving mammals like seals, which have evolved massive spleens to store extra oxygen for deep dives. Essentially, the Bajau are evolving in a way that allows them to survive underwater longer than the rest of us.
But that’s just the beginning. The Bajau’s extraordinary abilities extend beyond just an enlarged spleen. Their bodies have evolved in other ways to help them survive in extreme underwater conditions. One key adaptation is superior oxygen control. Their genes enhance something known as ‘peripheral vasoconstriction’, meaning their bodies naturally redirect blood flow to their brains and essential organs while diving. This means they remain oxygenated for longer, delaying any need to resurface.
Another advantage lies in their resistance to carbon dioxide buildup. Another genetic variation regulates carbonic anhydrase, an enzyme that prevents dangerous changes in blood pH levels. Normally, it’s the rising CO2 levels which trigger panic and force a person to breathe, but the Bajau’s bodies manage these shifts differently, allowing them to stay submerged for much longer without panic setting into their bodies.
But perhaps most astonishingly, the Bajau show genetic similarities to populations living at high altitudes. Their bodies have adapted to thrive in low-oxygen environments, making them naturally resistant to hypoxia or low oxygen levels.
While their genetics give them an advantage, the Bajau also take things to the extreme in ways that might make you cringe. Many intentionally rupture their eardrums at a young age. Because the deeper you dive, the more the pressure builds up in your ears. By bursting their eardrums early, they eliminate the risk of painful pressure buildup when diving deep. The downside? Many Bajau are partially or completely deaf by old age. It’s a brutal trade-off, but for them, the ability to dive deeper and hunt better is worth the sacrifice.
The Bajau are famous for their seemingly impossible diving feats. Some reports claim they can hold their breath for up to 13 minutes and dive as deep as 200 feet on a single breath.
The Bajau’s abilities aren’t just fascinating—they might help save lives in western societies too. Their natural resistance to low oxygen levels is similar to what happens during heart attacks, strokes, and high-altitude sickness. By studying their genetics, scientists hope to unlock new treatments that could help people survive medical emergencies where oxygen deprivation is a major risk.
But despite the intrigue, this incredible lifestyle and its people are disappearing.
Industrial fishing has made it harder for the Bajau to survive by hunting and gathering from the sea. Many governments are forcing them onto land, stripping them of their nomadic traditions. Since they don’t have official citizenship in most countries, they lack basic legal protections. As a result, fewer Bajau children are being raised with the diving traditions of their ancestors.
As their environment changes, so too might their genetic adaptations. If fewer Bajau continue their deep-sea diving lifestyle, their unique biology could fade over generations, lost to history.
So, next time you feel like a champ for holding your breath at your local swimming pool, remember the Bajau are out there, probably chuckling at your amateurish lung capacity.
