The Bajau are known as true sea nomads, moving through Southeast Asia and living off the riches of the seabed. Their lifestyle has been tied to diving for thousands of years, and their ability to hold their breath never ceases to fascinate scientists. A study suggests that the key to their extraordinary underwater performance lies in a larger spleen, which serves as a reservoir of oxygenated red blood cells.
Imagine a person who dives into the sea to hunt on the seabed, holding their breath for three or four minutes... or even longer. They might target fish or shellfish, but the goal is clear: to come back to the surface with something. While this sounds like the plot of a science fiction story, it is exactly what the Bajau people have been doing for thousands of years.
A Biological Diving Tank
The Bajau are poor and hardworking, and the so-called modern life is not necessarily kind to them. But after developing such a close relationship with the sea over centuries, it is not unreasonable to think that genetics would give them some specific advantage to adapt more efficiently to their environment.
A published study by Dr. Melissa Ilardo of the University of Copenhagen and a broad group of colleagues explains that the Bajau have a larger-than-normal spleen, by 50 percent to be precise. The spleen destroys old red blood cells and acts as a special reservoir of oxygenated cells.
One of the body's last resources to resist the depths (besides slowing the heart rate and constricting blood vessels in the extremities) is spleen contraction, which results in an injection of oxygen. In other words, the spleen behaves like a biological diving tank.
Another interesting aspect is that there is no size difference between Bajau who dive frequently and those who do not, so it is not strictly a matter of practice. The 50 percent figure was established by comparing the spleens of the Bajau with those of the Saluan people, who have generally been engaged in agriculture.
Of course, this is not simple curiosity; there is a legitimate interest in understanding the human body's ability to adapt to hypoxic situations. Oxygen deprivation can mean the difference between a recovery without sequelae or permanent damage, and the more we know about it, the better.
