Unveiling the Nano-Mirrors in Blue Sharks’ Skin: A Chameleon-like Color Change
Scientists have recently unveiled a fascinating aspect of blue sharks. These majestic creatures possess hidden nano-mirrors in their skin. These mirrors not only contribute to their vibrant blue coloration but may also enable them to change color akin to chameleons.
Researchers at the City University of Hong Kong stumbled upon intricate nanostructures within the sharks’ tooth-like skin scales, known as dermal denticles. These structures function as nature’s layered mirrors and light filters.
Dr. Viktoriia Kamska, a member of the research team, explained the mechanism behind this phenomenon. “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,” she said. The guanine crystals within the denticles’ pulp cavities act as blue reflectors, while melanin-containing vesicles absorb other wavelengths.
The research findings suggest that by altering the spacing between layers of guanine crystals—possibly triggered by environmental factors like water pressure—sharks could shift their color from blue to green or gold. This discovery signifies a completely different evolutionary path for color production compared to bony fish, given that sharks diverged from them hundreds of millions of years ago.