The rare square structure of a seahorse's tail could inspire the next generation of tough and flexible robots that can be used in surgery or search and rescue missions, scientists say.
The seahorse has an unusual skeletal structure, including a tail in which a vertebral column is surrounded by square bony plates.
Although technically a fish, the seahorse has a tail that through millions of years of evolution has largely lost the ability to assist the animal in swimming.
Instead, it provides a strong, energy-efficient grasping mechanism to cling to things such as seaweed or coral reefs, waiting for food to float by that it can suck into its mouth.
At the same time, the square structure of its tail provides flexibility; it can bend and twist, and naturally returns to its former shape better than animals with cylindrical tails.
This helps the seahorse hide, easily bide its time while food floats to it, and it provides excellent crushing resistance - making the animal difficult for predators to eat.
"Human engineers tend to build things that are stiff so they can be controlled easily," said Ross Hatton, an assistant professor in the College of Engineering at Oregon State University, and a co-author on the study.
"But nature makes things just strong enough not to break, and then flexible enough to do a wide range of tasks. That's why we can learn a lot from animals that will inspire the next generations of robotics," Hatton said.
Hatton said biological systems can combine both control and flexibility, and researchers gravitated to the seahorse simply because it was so unusual. They theorised that the square structure of its tail, so rare in nature, must serve a purpose.
"We found that this square architecture provides adequate dexterity and a tough resistance to predators, but also that it tends to snap naturally back into place once it's been twisted and deformed," Hatton said.
"This could be very useful for robotics applications that need to be strong, but also energy-efficient and able to bend and twist in tight spaces," he said.
Such applications, he said, might include laparoscopic surgery, in which a robotic device could offer enhanced control and flexibility as it enters a body, moves around organs and bones, and then has the strength to accomplish a surgical task.
It could find uses in industrial system, search and rescue robots, or anything that needs to be both resilient and flexible.
