Dolphin Skin, Shark Skin: The Secrets of Perfect Hydrodynamics

7/5/2025

In the mysterious depths of the ocean, every species has had to adapt to the relentless laws of physics to survive. Among the champions of hydrodynamics, dolphins and sharks dominate the waters, reaching impressive speeds and navigating with an ease that defies comprehension. Behind their performance lies an evolutionary secret: the structure of their skin.

The Dolphin's Secret: Intelligent Skin

Dolphins, true acrobats of the ocean, can slice through the water at speeds exceeding 50 km/h (31 mph). The common dolphin (Delphinus delphis), for example, is known for its bursts of speed and ability to surf the waves. Its secret lies partly in the dynamic structure of its skin. Composed of an elastic outer layer and a deeper layer of collagen, their skin absorbs and dampens water turbulence. This phenomenon, known as drag reduction, allows them to minimize resistance and conserve energy.

Studies have shown that dolphin skin contains microscopic folds that adjust according to hydrodynamic forces, reducing vortices that would otherwise slow them down. Some researchers are now drawing inspiration from this structure to design anti-friction materials for the naval and aerospace industries.

One notable example is the development of dolphin-inspired coatings for submarines and ships. Engineers have tested flexible hull materials that mimic dolphin skin’s ability to adjust to water pressure, leading to reduced fuel consumption and increased speed. This technology could revolutionize underwater transportation by making vessels more energy-efficient and maneuverable.

The Living Armor of Sharks

While dolphin skin is flexible and dynamic, shark skin is a true microscopic armor. Covered in tiny dermal denticles—small rigid structures similar to serrated scales—it plays a crucial role in their speed and maneuverability.

The great white shark (Carcharodon carcharias), for example, can reach speeds of up to 56 km/h (35 mph) thanks to this adaptation. The dermal denticles create a textured surface that channels water into fine layers, reducing drag and increasing swimming efficiency. This unique coating also limits the growth of algae and parasites, an evolutionary advantage that allows sharks to maintain optimal hydrodynamics without being slowed down by unwanted organisms.

Inspired by this adaptation, engineers have developed biomimetic coatings for ship hulls and swimsuits. In fact, some shark-skin-inspired swimsuits were banned from the Olympic Games after it was proven that they provided swimmers with an unfair advantage.

Sharkskin: The Banned Technology

In the 2000s, sports equipment manufacturers designed swimsuits inspired by shark skin, called sharkskin suits. These suits were covered with micro-relief structures mimicking the dermal denticles of sharks, reducing drag and improving buoyancy. They allowed swimmers to shave off crucial fractions of a second in competition.

Their effectiveness was so remarkable that at the 2008 Beijing Olympics, over 90% of medalists wore these suits, breaking numerous world records. In response to this disparity, the International Swimming Federation (FINA) decided to ban these swimsuits in 2010, arguing that they provided an artificial advantage beyond the athletes' natural abilities.

However, while based on the concept of shark denticles, these suits did not perfectly replicate the complex structure of real shark skin. Shark skin functions not only through its texture but also through the flexibility and dynamics of its denticles, which adapt to water flow. Despite its biomimetic inspiration, sharkskin technology remained an approximation of nature's perfection.

Why Can't Humans Compete?

Unlike dolphins and sharks, the human body is not designed for optimal hydrodynamics. Our smooth skin creates more friction with water, and our muscles are not optimized for efficient propulsion in this element. Even with cutting-edge equipment, we remain far from the natural efficiency of these marine predators.

Two Strategies, One Goal

Dolphins and sharks have taken different evolutionary paths to achieve the same result: fluid and efficient navigation. While dolphin skin adapts in real time to turbulence, shark skin stiffens and channels water flow. Two fascinating biomechanical solutions that highlight nature's ingenuity.

In laboratories worldwide, these natural marvels are inspiring innovations in fields ranging from maritime transport to sports equipment. Prototypes of dolphin-inspired submarines are being developed, and biomimetic underwater drones based on shark skin could one day revolutionize ocean exploration. Once again, the ocean proves to be an infinite reservoir of solutions for the future.

And beyond dolphins and sharks, other marine creatures hold secrets of hydrodynamic perfection. From the streamlined bodies of orcas to the undulating propulsion of cuttlefish, the ocean continues to challenge our understanding and inspire the next wave of human innovation.