Blue Sharks’ Secret Power

While sharks are well-known for their long, powerful bodies and diverse range of species, blue sharks also have another secret power: changing their bodies’ colors.

Because of the rarity of the color blue in ocean creatures, scientists at the City University of Hong Kong were curious as to how blue sharks’ bodies were a metallic bluish color, that is what makes the blue shark unique. The scientists found tiny nanostructures in the fish’s skin, which not only acted as blue reflectors, which is why blue sharks are the way they are, but could also be used to reflect other types of light, giving blue sharks the ability to change their bodies’ colors.

The scientists were shocked by this discovery because a design like this “hasn’t been seen before.”

Looking under a shark’s fin using a set of microscopes, the team found that guanine crystals, a component of DNA and RNA that allow animals to change colors, that are found in blue sharks, act as blue reflectors. Meanwhile, melanosomes, another type of structure, absorb wavelengths of light.

you create the special ability to be able to change color.

Professor Dean from the City University of Hong Kong described how even slight changes in the environment around blue sharks can affect the color of their scales. Something as simple as humidity or water pressure could make the blue shark seem lighter or darker. For example, if the shark swam deeper into the ocean, the water pressure would cause the guanine crystals to press more closely together, making the shark appear to be a darker shade of blue.

While scientists have a lot of the ocean world to discover, this is one of the many steps scientists will take to understand the ocean better.