(Web Desk) – Scientists have discovered that the shark’s tooth-like skin scales house guanine platelets and melanin vesicles that work together to produce a vivid blue hue.
What’s more, these nanostructures may actually shift depending on environmental conditions like water pressure, potentially allowing sharks to subtly change color as they move through the ocean.
A new study on the blue shark (Prionace glauca) has uncovered an intricate nanostructure within its skin that not only creates the shark’s signature blue hue but may also allow for subtle shifts in color.
“Blue is one of the rarest colors in the animal kingdom, and animals have developed a variety of unique strategies through evolution to produce it, making these processes especially fascinating,” says Dr. Viktoriia Kamska, a post-doctoral researcher in the lab of Professor Mason Dean at City University of Hong Kong.
Researchers found that the vivid blue appearance comes from structures located inside the pulp cavities of dermal denticles—tiny, tooth-like scales that form a protective layer over the shark’s skin. These cavities contain guanine crystals, which reflect blue light, and melanin-filled vesicles called melanosomes, which absorb other wavelengths.
The discovery also reveals that the shark’s trademark color is potentially mutable through tiny changes in the relative distances between layers of guanine crystals within the denticle pulp cavities. Whereas narrower spaces between layers create the iconic blues, increasing this space shifts the color into greens and golds.
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