In the sea, most of us are half-blind - but the Moken are king. This Southeast Asian tribe of sea gypsies can see twice as clearly underwater as Europeans, researchers have found.
The semi-nomadic Moken, who have settled on Thailand's Surin Islands, use their superior visual skills to dive for food on the ocean floor. It's not known whether the ability is learned or genetic.
Most of us see blurred images when we dive without goggles or a mask. The eye is adapted to air, and struggles to focus light under water. But Moken children can pick out small shells, clams and sea cucumbers at depths of three to four metres.
Moken children can distinguish underwater objects less than 1.5 millimetres wide; Europeans struggle to make out anything less than 3 mm across1, biologist Anna Gislén of Lund University, Sweden, and her colleagues found.
"They use the optics of the eye to the limits of what is [humanly] possible," says Gislén. The team compared the sub-aqua vision of native Moken and holidaying European kids, aged 7-14 years.
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