Who Are the Bajau?
The Bajau people live on houseboats among the islands of Malaysia, Indonesia, and the Philippines.
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They almost exclusively eat fish they catch from the sea and only go into local towns to trade or hide from extreme weather.
A Long History of Diving for Fish
While this tribe has many ways of catching fish to feed themselves, their preferred tactic is diving for fish—they’ve been doing so for hundreds of years.
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The Bajau sometimes use hand weights and goggles, but even with no other equipment, they can dive up to 100 feet to catch their dinner.
The Bajau People: Breath-Holding Contest Champions
In addition to being able to dive to great depths without equipment, the Bajau are also incredibly unique. On average, they can hold their breath more than six times the maximum time most humans can.
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In fact, while the average person can only hold their breath for a max of two minutes, people in the Bajau tribe can hold theirs for an average of thirteen!
Desperately Trying to Understand the Bajau People
In 2018, scientists wanted to understand how these people were able to dive to such great depths and stay under water for extended periods of time, so they began studying the Bajau tribe.
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What they found is something truly incredible and almost unbelievable: The Bajau people’s bodies had evolved and are different from any other human on earth.
Genetic Adaptations in the Bajau People
The first and most notable evolution of the bodies of the Bajau tribe is that their spleens are 50% larger than all other humans.
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When any human goes underwater and holds their breath, the spleen contracts and releases red blood cells to allow the body to increase oxygen capacity until they can breathe fresh oxygen again above water.
The Enlarged Spleen Changes Everything
Therefore, with a spleen 50% larger than the average human, the Bajau people have more red blood cells to be used for diving and holding one’s breath.
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It means they can carry more oxygen in their blood than the average person, and consequently, they don’t need to come up for air as frequently.
Differences in Genetic Make-up
Researchers also found that the PDE10A gene in the Bajau people had mutated. They believe this change is the reason why their spleens have increased so significantly in size.
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PDE10A is in charge of the thyroid hormone T4, which regulates low oxygen levels during times of stress and increased metabolic rates. Essentially, higher amounts of T4 in the body lead to an increased spleen size.
More Adaptations of the Bajau
As well as the increased T4 hormone and spleen size, the researchers noted the Bajau people also seem to have what they’re calling “diving-specialized genes.”
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For example, unlike other people, the Bajau tribe has a gene that prevents the occurrence of hypercapnia when diving, a problem that occurs when carbon dioxide is elevated in the blood after being underwater for extended periods of time.
Even the Bajau Peoples’ Lungs Have Changed Over Time
Richard Moon, a scientist at Duke University, reported the Bajau people also have lungs with much stronger walls that can withstand high amounts of blood.
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He explained that while other people experience ruptured lungs at deep depths, the Bajau do not, as their time spent underwater has led to the development of much stronger lungs.
Not the Only People on Earth With Exceptionally Strong Lungs
What’s especially interesting about Moon’s findings on the Bajau’s lungs is that other researchers have found this same phenomenon in Tibetan people, but for a very different reason.
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Tibetans live high in the Himalayan Mountains at altitudes over 15,000 feet. While the average person would struggle to breath in this setting, the evolved lung strength of the Tibetans allows them to live safely and comfortably on the “Roof of the World.”
The Bajau May Disperse Completely in Near Future
The research conducted on the Bajau people is incredibly important work for scientists attempting to understand the human body, as well as evolution as a whole.
Source: Mauricio Handler/National Geographic
Sadly, the Bajau live as a segregated and marginalized community, and have essentially dispersed due to industrial fishing. As they integrate into society, their physical traits will deteriorate, and scientists may struggle to ever truly understand how the Bajau body could do what it does.