Handout photo of the skeletal structure of a seahorse with its square cross section tail. Photo: Oregon State University/PA Wire

Seahorses have shown scientists that sometimes it is definitely hip to be square.

The tails of the marine oddities have a cross section that is square, not round or semicircular as in most other animals.

They evolved this way for good reasons, scientists have learned. The square structure allows the seahorse tail to be highly flexible and at the same time very strong.

After twisting it also returns to its former shape more easily than a cylindrical tail. And the square bony plates that support it provide excellent crushing resistance, making a seahorse difficult for predators to eat.

The lessons learned from studying the seahorse tail could aid the development of more energy-efficient robots, experts believe.

Square technology could soon find its way into robotic systems used in surgery, search and rescue, military applications and industry.

Ross Hatton, from Oregon State University, US, who co-led the research published in the journal Science, said: “Human engineers tend to build things that are stiff so they can be controlled easily. 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.

“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. 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.”

In keyhole surgery, a robotic device based on the seahorse tail could offer enhanced control and flexibility as it moves around organs and bones, he said. This would be combined with the strength needed to accomplish a surgical task.

The scientists compared the merits of cylindrical and square structures using computer simulations and three-dimensional printed models.

Handout photo models that show that a square cross section tail makes more contact with the surface it is gripping than a round tail. Photo: Michael Porter/Clemson University/PA Wire

They found that when a seahorse tail is crushed, the bony plates tend to slide past one another, acting as an energy-absorbing mechanism and protecting the central vertebral column. The plates can then snap back to their normal position with little use of energy.

“Understanding the role of mechanics in these biologically inspired designs may help engineers to develop seahorse-inspired technologies for a wide variety of applications in robotics, defence systems or biomedicine,” the researchers concluded.