Photo: An Olive sea snake (Aipysurus laevis) dives after taking a breath at the water's surface. Sea snakes are fully aquatic reptiles that live their whole lives at sea. Little is known about how they sense their underwater environment. Credit: Chris Malam After sea snakes left their land-bound cousins behind and took to water some 9 to 20 million years ago, they may have evolved a sense mechanism that lets them feel vibrations in the water and gather information about objects in the distance.
That was the suggestion behind a new study led by scientists at the University of Adelaide, who took a closer look at structures on the head of a snake called scale sensilla.
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Scale sensilla are raised structures on the heads of land snakes and some lizards. The creatures use them to sense objects in front of them directly, by touch (see photo below).
With the help of microscope imaging systems, the researchers studied 19 snake species – from land-based, to seafaring, to semi-aquatic – and gauged the number of scale sensilla present on individual scales in the creatures' heads as well as the shapes of the structures.
The researchers found that on sea snakes the scale sensilla tended to jut out more from the scales and were shaped differently – more like domes – than those of land snakes.
What's more, the scale sensilla covered larger areas of a sea snake's body.