The Bajau People Are Evolving for Life Underwater

For at least 1000 years, the Bajau people of Southeast Asia have lived in close proximity to the ocean. Bajau fishermen spend up to 60 percent of their day underwater and can dive more than 70 meters down using only homemade goggles.

With such an affinity for water, scientists have suspected the Bajau might have adapted physically to their aquatic lifestyle. A recent study found that the Bajau have oversized spleens, a trait typically found in deep-diving marine mammals, such as seals and sea lions.

The spleen is a reservoir for red blood cells, which are expelled during deep dives. These blood cells give the diver an extra boost of oxygen when it is needed most.

The study also found that the Bajaus’ large spleens are likely the result of genetic changes because the Bajau possess a gene mutation not found in their landlubbing cousins the Saluans.

The mutation affects PDE10A, the gene that ramps up thyroid hormone and makes spleens grow larger, at least in mice. The evidence suggests the Bajau are evolving to match their submarine lifestyle, which begs the question…given enough time could evolve mermaid-like abilities?