Bajau: Can Humans Breathe Underwater?
Can Humans Breathe Underwater? The Bajau "Sea Nomads" and the Genetic Mutation for Super Diving
Can humans breathe underwater? Not exactly — but the Bajau people of Southeast Asia have evolved a genetic mutation that gives them extraordinary diving abilities, including spleens 50% larger than average. Bajau sea nomads, human underwater adaptation, genetic mutation diving, Bajau spleen size, sea nomad gene, Bajau people, free diving abilities, human evolution underwater, Bajau genetics, and "sea nomad gene" — these are the searches driving scientific and medical news right now. The Bajau, often called "sea nomads" or "sea gypsies," have lived on houseboats in the waters of Indonesia, Malaysia, and the Philippines for over 1,000 years, spending up to 60% of their working day underwater. Read more about human evolution →
Research published in the journal Cell reveals that the Bajau have developed genetic adaptations that allow them to dive to depths of over 70 meters (230 feet) using nothing more than a wooden mask and a weight belt. Some claim to hold their breath for up to 13 minutes. The secret lies in a larger spleen — the organ that acts as a biological "scuba tank" by releasing oxygenated red blood cells when the body is submerged in water. Read more about genetics →
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When Melissa Ilardo, a graduate student at the University of Copenhagen, first heard about the Bajau, she was fascinated. She packed a portable ultrasound machine and traveled to Indonesia to measure the spleens of the Bajau and compare them to a neighboring farming community called the Saluan. What she found was remarkable.
The Bajau's spleens were 50% larger than those of the Saluan on average. The spleen is a fist-sized organ located close to the stomach. It removes old cells from the blood and acts as a reservoir for oxygenated red blood cells. When a person holds their breath and submerges their face in cold water, the spleen contracts, releasing these red blood cells into the bloodstream and providing an oxygen boost.
The larger spleens of the Bajau are not simply a result of frequent diving. Non-divers within the Bajau community also had similarly enlarged spleens, suggesting a genetic basis for the adaptation. The researchers then scanned the Bajau genome and identified 25 sites that differed significantly from comparison populations. One site on a gene known as PDE10A was found to be correlated with larger spleen size.
There's not a lot of information out there about human spleens in terms of physiology and genetics, but we know that deep diving seals, like the Weddell seal, have disproportionately large spleens. According to Ilardo, the Bajau have an adaptation that increases thyroid hormone levels and therefore increases their spleen size.
How the Bajau Dive: A Day in the Life of a Sea Nomad
The Bajau live an amphibious existence. They are born on houseboats called lepas, learn to swim as toddlers, and begin fishing and diving as young as eight years old. A typical diving day lasts about eight hours, with divers spending more than 60% of that time underwater. They dive repeatedly, often for 30 seconds to several minutes at a time, reaching depths of over 70 meters.
Their traditional equipment is remarkably simple: a wooden mask or goggles and a weight belt. They hunt fish, sea cucumbers, abalone, and spider conches with handmade spears.
According to Bilkuin Jimi Salih, a 20-year-old Bajau Laut member, they are very comfortable in the water. One of their specialties is that, because they live on the sea and are always in the sea, they can dive in the water for a long time. They learn by observing and from there develop their own technique.
The Diving Response: Why the Spleen Matters
The Bajau's diving abilities are tied to a physiological response that all mammals share — the diving response. When the face is submerged in cold water, the heart rate slows, blood vessels in the extremities constrict, and the spleen contracts. This contraction releases oxygenated red blood cells into the bloodstream, boosting oxygen levels by up to 9%.
A larger spleen means a larger reservoir of red blood cells and a greater oxygen boost during dives. The Bajau have evolved this adaptation to sustain their long and frequent dives.
The Bajau's Future: A Way of Life Under Threat
Despite their extraordinary adaptations, the Bajau's traditional way of life is disappearing. Overfishing, commercial fishing, and climate change are depleting fish stocks, making it increasingly difficult for the Bajau to survive through traditional fishing practices.
According to Salih, they could easily get a bucket of abalone and sea cucumbers before, but now there's hardly any. Other high-value fish are also available less. So for them to rely on the sea as a source of living is now very difficult and very challenging.
Many Bajau are abandoning their houseboats for stilt houses, adopting a more sedentary lifestyle. The cost and complexity of maintaining a lepa is becoming unaffordable, and the shift to land makes them less adaptable and more reliant on specific areas. Additionally, many Bajau are stateless, lacking formal citizenship and access to education, healthcare, and other basic services.
FAQ: Humans Underwater and the Bajau
Q: Can humans breathe underwater?
A: No. Humans cannot breathe underwater. However, the Bajau people have evolved genetic adaptations that allow them to hold their breath for extended periods while diving.
Q: What is the "sea nomad gene"?
A: The "sea nomad gene" refers to a genetic variant in the PDE10A gene that is associated with larger spleen size in the Bajau people. This adaptation allows them to stay underwater longer.
Q: How deep can the Bajau dive?
A: The Bajau can dive to depths of over 70 meters (230 feet) using only a wooden mask and a weight belt.
Q: How long can the Bajau hold their breath?
A: Some Bajau claim to hold their breath for up to 13 minutes, though typical dives are much shorter. Research shows they spend about 60% of their working day underwater.
Q: Are the Bajau the only people with this adaptation?
A: No. Other diving populations, such as the Japanese pearl divers, also show some adaptation, though the Bajau's adaptation is particularly pronounced due to their prolonged isolation and marine-dependent lifestyle.
Q: Is the Bajau lifestyle under threat?
A: Yes. Overfishing, commercial fishing, climate change, and statelessness are threatening the Bajau's traditional way of life. Many are abandoning their houseboats for stilt houses on land.
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