A tribe of nomadic divers has evolved larger spleens to allow them to catch fish more than 200 feet underwater, scientists have discovered.

For more than 1,000 years the Bajau population of Indonesia, has travelled the southeast Asian seas in houseboats, collecting fish and seafood by free diving with spears.

Their nautical, itinerant lifestyle has earned them the nickname ‘sea nomads’ or ‘sea gypsies.’

But now scientists have discovered the secret to their astonishing fishing prowess. They have evolved genetically enlarged spleens which allows them to use oxygen more efficiently so they can stay underwater for longer.

Study leader Melissa Ilardo of Cambridge University spent several months in Jaya Bakti, Indonesia taking genetic samples and performing ultrasound scans of the spleens from both the Bajau and their land-dwelling neighbours, the Saluan.

The results were sequenced at the University of Copenhagen and clearly showed the Bajau have a median spleen size which is 50 per cent larger than the Saluan.