I am a blue mind who has a strange love for the water and a deep affinity for the sea. Unfortunately, I can’t hold my breath underwater for more than a minute. The average person, without training in static apnea, can hold their breath underwater for up to two minutes with the help of breathing in pure oxygen beforehand. Now, picture a tribe of individuals from Southeast Asia who are genetically adapted to survive underwater without oxygen for an average of 13 minutes. The Bajau Laut people have evolved physiologically and genetically, acquiring new features that essentially turn them into human seals.
The diving reflex is a series of automatic responses that happen when an air-breathing mammal’s face is submerged in water. Blood vessels constrict, the spleen contracts, and heart rate slows down in response to low oxygen levels. The Bajau people are a seafaring, nomadic fishing clan who spend a significant portion of their lives deep-diving underwater. Research has found that they may have evolved to have larger spleens, up to 50% bigger than the average person, which allows them to maintain the diving reflex for longer periods while underwater.
Living on houseboats known as lepas, the Bajau subsist on fishing and have traditional methods of diving, using wooden goggles and hand weights to catch fish as deep as 30 meters underwater. Genetic studies have shown that even members of the tribe who do not dive have the genetic mutation for an enlarged spleen, possibly due to a specific gene controlling a thyroid hormone that increases metabolic rates and combats low oxygen levels.
Other genetic adaptations found in the Bajau help to redirect blood flow to essential organs during dives and prevent hypercapnia, a condition caused by elevated carbon dioxide levels in the blood. The Bajau, like the Tibetans, may have developed these adaptations due to suffering from hypoxia in older generations, a condition characterized by oxygen deficiency in the tissues.
Studying the Bajau and their unique adaptations to diving could provide valuable insights into managing hypoxia. Marginalization and segregation have made life challenging for the Bajau in their native habitats, as they are not recognized as equals by the countries in which they live. As thousands of them migrate from the seas due to increased industrial fishing, there is a fear that their unique genetic adaptations may be lost before scientists can fully understand and study them.
