Seahorses have unusual tails, and now researchers have used a 3D printer to create models of the distinctive appendages in order to test their structure. Doing so led to a surprising discovery that could have far-ranging consequences in technology.

Seahorse tails are composed of a series of square prisms, connected by joints, and each segment of the tail is protected by bony plates. This is a highly-unusual shape, as the tail segments of most animals are cylindrical.

Oregon State University researchers, together with colleagues from Clemson State, wanted to know if this square shape of these tails provided an advantage to the aquatic animals. To do this, they created models of the distinctive tail of seahorses, as well as of a theoretical cylindrical version of the appendage. Each of the objects were subjected to physical stresses, including crashing into other objects.

"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," said Ross Hatton from the College of Engineering at Oregon State University.

Seahorses are a type of fish, but they are unable to undertake powered swimming. Instead, they use their tails to firmly grasp onto objects such as seaweed. While anchored, the creatures consume tiny particles of food that float near their perch. Researchers found the unusual shape of the tail structures provides great flexibility, and is better able to return to its normal shape better than the rounded version of the appendage. The shape also makes seahorses difficult to crush, adding to their natural defenses. When pressed together, the bony plates slide past each other, absorbing energy.

Other defense systems, as well as biomedicine, could benefit from the new study. One possibility is advancing laparoscopic surgery, in which a device is placed in a small incision in a patient, in order to carry out repairs elsewhere in the body.

Search and rescue robots could also benefit from tails or arms with square segments, as such limbs would be both strong and flexible, each desirable characteristics in a mechanical devices searching through debris or other hostile environments.

"We haven't gotten that far with the applications side of things yet, but we see a lot of potential with this device because it's so unique," Michael Porter of Clemson University, said.

Development of the 3D-printed seahorse tails and examination of their unique structure was detailed in the journal Science.

Photo: Alex Griffioen | Flickr