In a rare case of natural selection in modern humans, the free-diving Bajau people have developed a larger spleen.
Native to Malaysia and the Philippines, the Bajau are renowned for their incredible ability to remain underwater for minutes at a time to catch fish and other creatures directly off the sea floor.
On some days, fishermen can remain underwater for a cumulative total of more than five hours.
Now researchers who have been attempting to find out what enables this remarkable talent have discovered that a genetic mutation appears to have given the Bajau an abnormally large spleen.
This adaptation is beneficial as the spleen is known to release oxygenated red blood cells, thus making it possible to stay underwater for longer.
The study authors are hoping that the discovery could help with the development of new treatments for respiratory illnesses.
"Overall, our results suggest that the Bajau have undergone unique adaptations associated with spleen size and the diving response, adding new examples to the list of remarkable genetic adaptations humans have experienced in recent evolutionary history," they wrote.