Asian Scientist (September 4, 2024) – The great white shark is one of the most efficient predators, known for its strength and speed, and holds the secrets to designing faster airplanes and ships. A new study published in Royal Society magazine interfaceRevealed how denticles, or tooth-like structures in shark skin, help reduce friction, allowing sharks to swim efficiently at different speeds. This reduction in friction is crucial to their speed and endurance, making them agile hunters and long-distance swimmers, capable of swimming distances of up to 20,000 kilometers.
The study, conducted by scientists at Tokyo Institute of Technology, found that these small teeth have high and low ridges that affect how fast the shark moves. High ridges are more effective at lower speeds, while a combination of high and low ridges works best at higher speeds, allowing the shark to conserve energy while cruising or hunting.
Associate Professor Hiroto Tanaka, one of the study’s lead authors, said the design allows the shark to move efficiently during slow, steady swimming, as well as when fast bursts of speed are required.
These findings can inspire new designs in engineering. Engineers have long been interested in the tiny teeth of migrating sharks, using them as models to create ribs — small, one-way ridges that reduce friction in airplanes and sailboats. However, the complexity of the shape, size, and spacing of the denticles on a shark’s body makes it difficult to fully understand how they work together to minimize resistance to movement.
To reveal this complexity, the researchers developed a 3D model of the white shark’s denticles and analyzed the hydrodynamic properties of the mid-high and low lateral ridges in relation to the shark’s swimming speed. They found that these structures are optimized to reduce drag at all speeds, allowing sharks to hunt at great speeds and travel long distances using minimal energy.
For the study, researchers collected skin samples from 17 different parts of the great white shark’s body, including its nose, dorsal fin, side and ventral body, tail fin and pectoral fin. These samples were scanned using a microfocus X-ray CT scanner to build detailed 3D models. By measuring the spacing and height of the ridges, the researchers were able to determine how efficiently the shark’s skin interacted with the turbulent eddies in the water. Their results show that the design of these small teeth can effectively reduce drag during slow cruising and fast hunting.
“High ridges may reduce drag at low swimming speeds, while alternating high and low ridges may reduce drag at high swimming speeds, covering the entire range of swimming speeds,” Tanaka said.
Research also suggests that megalodon, an extinct giant shark, may have swam at a similar speed to the great white shark. In addition to new engineering designs, the findings could help scientists study shark evolution.
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Source: Tokyo Institute of Technology; Image: Shutterstock
Please refer to the article: The three-dimensional shape of the great white shark’s natural ribs: the relationship between the shark’s tooth shape and swimming speed
Disclaimer: This article does not necessarily reflect the views of Asia Scientists or its staff
