Thicker and Tougher with Age

What gives shark skin its unique toughness and smooth, hydrodynamic edge? The secret lies in dermal denticles – tiny, tooth-like scales made of the same material as our teeth. These microscopic armor plates don’t just make sharks sleek swimmers; they also shield their bodies from damage. But how do these denticles change as sharks grow – and do male and female sharks have different designs?

Researchers dove deep into these questions by studying bonnethead sharks, close relatives of hammerheads. Using electron microscopy, they captured incredibly detailed images of the sharks’ skin, analyzing how denticle shape, size, and texture evolve across different life stages. Their findings revealed that as sharks mature, their denticles develop more ridges and change in orientation – enhancements that likely improve swimming efficiency and protection. Interestingly, while researchers expected major differences between the sexes, they found only one: males had slightly steeper ridge angles. This research not only sheds light on how sharks are built for survival and reproduction but could also inspire future innovations in swimwear and biomimetic design.

“Shark skin is far more dynamic than people realize,” said Marianne E. Porter, Ph.D., senior author and an associate professor of biological sciences in FAU’s Charles E. Schmidt College of Science. “Our study shows that as bonnethead sharks grow, their skin doesn’t just get bigger – it transforms in ways that improve swimming performance and provide greater protection. These changes help reduce drag in the water and strengthen the skin against physical challenges like predators or mating-related injuries. It’s a remarkable example of how nature fine-tunes biological structures to meet the changing demands of an animal’s life.”

Read the press release.