The robot was developed to investigate why animals switch between different gaits, according to the Swiss Federal Institute of Technology in Lausanne (EPFL).

"Previous research has shown that animals change their gait to save energy and avoid musculoskeletal injuries," explained robotics researcher Milad Shafiee in the EPFL press release. However, experiments with animals and robots have shown that these explanations do not always apply.

The EPFL researchers surmised that animals also change their gait in order to avoid falling. To investigate this in more detail, they taught the robot to move independently on different surfaces.

Robots for biological research

This showed that the robot switched from walking to trotting on flat terrain to avoid falling over. And when the robot was confronted with holes in the ground, it switched from trotting to a so-called bounce jump. This is a kind of jump with stiff legs, like antelopes or cats do when they are frightened.

The so-called viability, i.e. the ability not to fall, was therefore the only factor that was improved by such gait changes. 

"It seems that energy efficiency, which was previously thought to be the driving force behind such transitions, is more of a consequence. When an animal is moving in difficult terrain, its first priority is probably not to fall," says Shafiee.

According to EPFL, the researchers hope that robots will be increasingly used in biological research in the future to reduce reliance on animals and the ethical concerns associated with this.