Latest news with #colour change
BBC News
11-07-2025
- Science
- BBC News
Blue sharks can change colour to camouflage say scientists
Blue sharks get their name from being, well, blue! But did you know that's one of the rarest colours in the animal kingdom? Scientists at the City University of Hong Kong looking at what makes this fish this colour found it's down to tiny nanostructures in their skin, which act as blue reflectors. Other structures also absorb other types of light - which help to produce the shark's characteristic colour. But not only that, the sharks' skin can change colour too. The team say a multi-functional design like this "as far as we know, hasn't been seen before". Read on for more. The research shows the secret to the blue shark's colour lies in the tooth-like scales on its guanine crystals act as blue reflectors while another structure, called melanosomes, absorb other wavelengths of colour. Professor Dean from the City University of Hong Kong said: "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 colour." The researchers had to look at a shark's fin really closely under lots of powerful microscopes. They used simulations on a computer to recreate and understand the structures under different Dean continued: "Very fine scale alterations resulting from something as simple as humidity or water pressure changes could alter body colour, that then shape how the animal camouflages or counter-shades in its natural environment." The research suggests even something as simple as swimming deeper in the ocean could make the sharks look a deeper colour of blue as the guanine crystals are forced closer together with the increased pressure from the water.
The Independent
11-07-2025
- Science
- The Independent
Scientists discover shark that changes colour like a chameleon
Unique structures on the skin of the blue shark suggest it may be able to change colour like a chameleon, according to a new study. The study, presented this week at the Society for Experimental Biology conference in Antwerp, reveals tiny nanostructures in the skin of the blue shark, Prionace glauca, that produce their colouration. The secret to the shark's colour lies in the pulp cavities of the scales that armour the skin, known as dermal denticles. 'Blue is one of the rarest colours in the animal kingdom, and animals have developed a variety of unique strategies through evolution to produce it, making these processes especially fascinating," Viktoriia Kamska, a researcher who participated in the study, said. Crystals of the molecule guanine within the pulp cavities act as blue reflectors. In addition, cell components containing the pigment melanin absorb other wavelengths to produce the shark's characteristic colour. '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," Dr Kamska explained. The melanin collaborates with guanine crystals of specific thickness and spacing to enhance the shark's colour saturation of the skin. "When you combine these materials together, you also create a powerful ability to produce and change colour," Mason Dean, another researcher, said. "What's fascinating is that we can observe tiny changes in the cells containing the crystals and see and model how they influence the colour of the whole organism.' The research was made possible by advanced imaging techniques to characterise the form, function and architectural arrangements of the tiny colour-producing structures. "We started looking at colour at the organismal level, on the scale of meters and centimetres, but structural colour is achieved at the nanometer scale, so we have to use a range of different approaches," Dr Dean said. Researchers then used computational simulations to confirm which structural parameters of the tiny skin structures were responsible for producing the observed appearance. They showed that this mechanism of colour change could also be driven by environmental factors that would affect the guanine crystal spacing. "In this way, very fine-scale alterations resulting from something as simple as humidity or water pressure changes could alter body colour, which then shapes how the animal camouflages,' Dr Dean said. When the shark swims deeper, for instance, more pressure acts on the skin, causing the guanine crystals to be pushed together and darken the shark's colour to better suit its surroundings. The mechanism by which these tiny structures behave may also be changing the shark's skin colour. "Such a multi-functional structural design – a marine surface combining features for high-speed hydrodynamics and camouflaging optics – as far as we know, hasn't been seen before,' Dr Dean said.
