The Bajau tribe, also known as the “sea gypsies”, is an ethnic group that has lived for centuries in the waters of Southeast Asia, particularly in the coastal areas of the Philippines, Malaysia and Indonesia. They are known for their nomadic life at sea and their deep relationship with the ocean, as they have traditionally depended on fishing, sea food gathering, and diving to survive.
A notable aspect of the Bajau tribe is their ability to dive to considerable depths without the use of specialized equipment, which has earned them a reputation as skilled free divers. The Bajau have developed diving techniques that allow them to remain submerged for long periods of time, often to obtain shellfish and fish, which has contributed to their unique identity and their adaptation to living in close relationship with the sea.
How does the Bajau tribe achieve this?
The genetic adaptation of the Bajau tribe to free diving offers a fascinating example of natural selection in action. Members of this community have acquired, over generations, physical and physiological characteristics that make them exceptionally skilled at submerging and remaining underwater for long periods of time.
Splenomegaly.
One of the genetic traits notably associated with this ability is splenomegaly, which is nothing more than the enlargement of the spleen.
The Immersion Reflex.
This is a reflex that guarantees survival during diving. In this situation of hypoxia or low oxygen depletion, the heart beats more slowly and the constriction of peripheral blood vessels diverts blood from the extremities to vital organs. At this moment the Spleen comes into action.
It has been proven that in this population the Spleen is 50% larger than in other people. This organ plays a crucial role in diving, as it behaves as a small store of red blood cells, releasing them in response to stress and allowing Bajau divers to perform long dives more effectively. Increased lung capacity and improved response to freediving have also been observed in this population.
Genetic mutations.
Genetic studies have shown some genetic mutations present in this tribe that give them these useful qualities:
Mutation of the PDE10A gene: located on chromosome 6, it intervenes in various metabolic functions.
Mutation of the BDKRB2 gene: located on chromosome 14, it is associated with vasodilation during the immersion process.
This adaptive evolution provides a compelling example of how natural selection operates in the context of the specific environmental pressures facing a population. In this case, the ability to obtain food from the sea through free diving has provided a significant advantage to individuals with certain genetic adaptations, which in turn has increased the likelihood that these characteristics will be passed on to future generations.
Most members of the Bajau tribe are Muslims and usually live in floating settlements or in houses built on stilts in shallow waters. This life linked to the sea has deeply influenced their culture, spiritual beliefs and traditions associated with the ocean. Likewise, the Bajau community has developed its own language, Bajo, which is an Austronesian language and forms part of its distinctive cultural identity.
In contemporary times, however, traditional Bajau life has been challenged by a number of factors, such as pressure from state authorities to settle on the mainland and the reduction of fishing grounds due to overexploitation and environmental degradation.
In short, the Bajau tribe is a unique and fascinating community that has developed a sea-adapted way of life over generations, with deep cultural and spiritual ties to the ocean. Their history, traditions and lifestyle offer valuable testimony to the human relationship with the environment and the cultural diversity in Southeast Asia.
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