SCIENTISTS DISCOVER MYSTERIOUS REASON FOR THE CHANGE OF COLOR IN BLUE SHARKS

They found that this was made possible by nanostructures in the skin that reflected the color blue.

The secret to the Blue Sharks’ ability to change color is in their tooth-shaped scales. Guanine crystals act as blue reflectors, while other structures called melanosomes absorb other colors. Professor Dean, a scientist from the City University of Hong Kong, says, “These components are packed into separate cells, reminiscent of bags filled with mirrors and bags with black absorbers, but kept in close association so they work together. When you combine these materials together, you also create a powerful ability to produce and change color.” This means that these scales can each change color independently of each other. Scientists say that this is a feature unique to Blue Sharks.

The researchers had to examine the sharks’ fins closely under high-power microscopes. Dr. Dean says, “Very fine scale alterations resulting from something as simple as humidity or water pressure changes could alter body color, that then shape how the animal camouflages or counter-shades in its natural environment.” For example, a change in the depth of the water would cause a deeper shade of blue because of the higher water pressure compressing the guanine particles together.

Link to article:

https://www.bbc.co.uk/newsround/articles/c20nj887w5vo