The strange skin of the teeth of the blue sharks allows them to change color to green and even gold

A new investigation has revealed that the pulp found in the “adapted teeth” of shark skin may allow them to change color.

According to, the shark in question is the blue shark (Prionace glauca), famous for being, as the name indicates, blue. It may not seem impressive to an animal with that name, but true blue is hard to find in the natural world.

“Blue is one of the rarest colors in the animal kingdom, and animals have developed a variety of unique strategies throughout the evolution to produce it, which makes these processes especially fascinating,” he said Viktoriia Kamskapostdoctoral researcher at the teacher’s laboratory Mason Dean Na City University De Hong Kong, Num.

The new investigation, presented at the Annual Conference of the Society of Experimental Biology in Antwerp, Belgium, on July 9, revealed a unique nanostructure on the skinned skin of blue sharks that not only explains your iconic coloration, as well as suggests that They can change color.

Everything comes down to your Strange dermal Dentulesa tooth -shaped scale that acts as a kind of armor. Like teeth, they have pulp cavities and contain guanine crystals and melanosomes. Guanine reflects blue, while melanosomes absorb other wavelengths of light.

“When these materials are combined, a powerful ability to produce and change color”Explained Dean.

“The fascinating thing is that we can observe small changes in cells that contain crystals and model as influence the color of the whole organism.”

Apart from explaining what makes the blue shark so intensely blue, it seems that, through the same mechanism, this color can change to shades of green and even golden.

This results from changes in spacing between guanine crystal layers in dental pulp cavities: The tighter, the more blue the shade; With more space, green appear.

The most intriguing is that these changes in spacing can be influenced by environmental changes.

An example given by the researchers is the depth: The deeper, the higher the water pressure, compressing the layers and producing a darker blue – which can be advantageous for sharks, making them more camouflaged in low light environments.

“These denticles not only give hydrodynamic benefits and antifouling The sharks, as we now find that they also play a role in production (and perhaps in change) of color, ”said Dean.

“One design Multifunctional structural like this – a marine surface that combines features for high -speed hydrodynamics and camouflage optics – as much as we know, has never seen before. ”

“As nanofabrication tools evolve, this field becomes a authentic recreation to study how structures lead to new functions. We know a lot about how other fish produce colors, but sharks and rays have diverged from bone fish for hundreds of millions of years – which represents a completely different evolutionary path in color production. ”