The research team at City University of Hong Kong has made a groundbreaking discovery in understanding the anatomy of blue sharks (Prionace glauca). Led by Dr. Viktoriia Kamska, they have revealed a unique nanostructure in the shark’s skin that produces its iconic blue coloration. This remarkable mechanism lies within the pulp cavities of the tooth-like scales – known as dermal denticles – that armor the shark’s skin.

The secret to the shark’s color lies in the combination of guanine crystals, which act as blue reflectors, and melanin-containing vesicles called melanosomes, which absorb other wavelengths. This collaboration between pigment (melanin) and structured material (guanine platelets of specific thickness and spacing) enhances color saturation.

When these components are packed together, they create a powerful ability to produce and change color. Dr. Kamska explains that the cells containing the crystals can be observed to see how they influence the color of the whole organism. This anatomical breakthrough was made possible using a range of imaging techniques, including fine-scale dissection, optical microscopy, electron microscopy, spectroscopy, and computational simulations.

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. Increasing this space shifts the color into greens and golds. Dr. Kamska and her team have demonstrated that this structural mechanism of color change could be driven by environmental factors such as humidity or water pressure changes.

For example, the deeper a shark swims, the more pressure its skin is subjected to, which should darken the shark’s color to better suit its surroundings. The next step is to see how this mechanism really functions in sharks living in their natural environment.

This research has strong potential for bio-inspired engineering applications. Dr. Kamska notes that structural coloration reduces toxicity and environmental pollution compared to chemical coloration. It could be a tool to improve environmental sustainability within the manufacturing industry, especially in marine environments where dynamic blue camouflage would be useful.

As nanofabrication tools get better, this creates a playground to study how structures lead to new functions. The research has been presented at the Society for Experimental Biology Annual Conference in Antwerp, Belgium on July 9th, 2025, and is being funded by Hong Kong’s University Grants Committee and General Research Fund.

The latest research from the University of British Columbia has shed light on an intriguing phenomenon – why male guppies have such striking and varied colors and patterns. A team of zoologists, led by Drs. Wouter van der Bijl and Judith Mank, conducted a comprehensive study to investigate this evolutionary mystery.

Their findings, published in Nature Ecology & Evolution, reveal that the more orange a male guppy is, the more virile it appears to be. The researchers used a combination of deep learning, genetic studies, and selective breeding to explore this connection. They bred three generations of increasingly orange guppies, observing significant differences in behavior.

What they discovered was striking – the most colorful males were up to two times more sexually active than their less vibrant counterparts. These orange guppies performed for females at a greater rate, for longer periods, and attempted to sneakily copulate more often. This suggests that color plays a crucial role in attracting mates and showcasing genetic fitness.

Interestingly, the researchers found that female guppies have a clear preference for males with unique, orange patterns. However, what’s remarkable is that this color diversity comes from the same cells responsible for forming the brain. This genetic link implies that guppy appearance and behavior are closely tied, with more colorful individuals potentially being healthier and fitter.

The study also uncovered the vast genetic architecture behind guppy coloration. The researchers identified seven orange and eight black color types, which can combine to produce 32,768 unique pattern combinations. This staggering diversity highlights the importance of genetic variation in evolution, allowing species to adapt to changing environments and conditions, such as climate change or disease.

As Dr. van der Bijl notes, “Genetic variation is the raw material that evolution uses to produce resilient, adapted animals and plants.” This research provides valuable insights into the intricate relationships between genetics, behavior, and environment in guppies, and has broader implications for our understanding of evolutionary processes in other species as well.

The study of lemurs has long fascinated scientists, and a recent research breakthrough by biological anthropologist Elaine Guevara is shedding new light on the primate’s remarkable ability to age without inflammation. This phenomenon, known as “inflammaging,” is a widespread issue in humans, leading to health problems such as heart disease, strokes, diabetes, cancer, and osteoarthritis.

Guevara’s research focused on ring-tailed and sifaka lemurs, two species that differ in their life pacing and lifespan. By studying these primates, Guevara aimed to understand why they avoid the inevitability of inflammaging observed in humans. Her findings were surprising: neither species showed age-related changes in markers of oxidative stress or inflammation. In fact, ring-tailed lemurs even exhibited marginal declines in inflammation with age.

This discovery, consistent with recent studies on other non-human primates, suggests that inflamaging is not a universal feature of primates, and perhaps not even a universal feature of humans. Christine Drea, a professor of evolutionary anthropology who worked alongside Guevara, notes that this study points to differences in aging between humans and lemurs.

As we grow older, low-grade chronic inflammation sets in, causing a range of health problems. Understanding why inflamaging increases with age in humans, what causes it, and how it can be prevented is critical information for unlocking ways to help humans live longer and healthier lives. Guevara’s study serves as the first step in unraveling these questions.

The next step for Guevara and her team is to conduct similar research on lemurs in their natural habitat. This will provide valuable insights into how aging can differ between captivity and the wild, and whether inflamaging is intrinsic or environmental.

With a rapidly aging global population, these findings are essential for mitigating disability and improving quality of life in later years. Guevara’s breakthrough study offers new hope that we may be able to learn from lemurs’ remarkable ability to age without inflammation, leading to better health outcomes for humans worldwide.