The Bajau people of Southeast Asia are commonly called “sea nomads” or “sea gypsies” for their traditional seafaring lifestyle. For generations, the Bajau people have built their homes above the water and spend most of their time at sea. And, from this oceanic lifestyle, they have developed the ability to hold their breath for extraordinary periods of time.
Scientists recently revealed that this ability is not by chance, but rather a result of adaptations which have their roots in the Bajau people’s DNA. In a paper written in the journal Cell, experts say over time the Bajau people have undergone natural selection, resulting in certain versions of genes becoming widespread, many of which are linked to biological changes.
One of these changes is the Bajau have developed a larger spleen, that could help the Bajau to hold their breath underwater for many minutes at a time.
But while the Bajau people’s talents have long been known, it was unclear whether the skill was the result of practice. The team says the findings could eventually prove useful in medical settings, potentially allowing experts to identify patients that might be at greater risk of death if they experience a lack of oxygen, for example during surgery.
“There seems to be so much to learn from the Bajau and other diving populations about how the human body is able to react to oxygen deprivation, which is an important medical issue,” said Dr Melissa Ilardo, first author of the study who was at the University of Copenhagen at the time of the research.
Scientists reveal how they unpicked the mystery following a clue from previous research: species of seals which can dive for longer have larger than expected spleens – an organ which, among its functions, can store oxygen-carrying red blood cells.
As a result the team used an ultrasound device to measure the spleen in 43 Bajau people and 33 people from a neighboring group of farming people, the Saluan.
“The spleen size is about 50% larger in these sea nomads than it is in the [Saluan], so already it was like ‘Oh my God – it is really [an] extreme physiological characteristic,” said Prof Eske Willerslev, a co-author of the study from the University of Cambridge.
A large spleen means even more oxygen-carrying red blood cells can be pumped into the circulatory system when the organ contracts, allowing individuals to stay underwater for longer. [The Gaurdian]