Australasian Science: Australia's authority on science since 1938

Robots May Need Lizard-Like Tails for Off-Road Travel

Robots may one day tackle obstacles and traverse uneven terrains after collaborative research analysed the nuanced movement of eight species of Australian agamid lizards that run on two legs.

PhD candidate Nicholas Wu of the University of Queensland said the study, published in the Journal of the Royal Society Interface (, challenged mathematical models based on the animals’ movement. “There was an existing understanding that the backwards shift in these lizards’ centre of mass, combined with quick bursts of acceleration, caused them to start running on two legs at a certain point,” he said.

“It’s just like a motorcycle driver doing a ‘wheelie’. What we found, though, is that some lizards run bipedally sooner than expected by moving their body back and winging their tail up. This means that they could run bipedally for longer, perhaps to overcome obstacles in their path.”

Lead author Dr Christofer Clemente from the University of the Sunshine Coast said the results may have important implications for the design of bio-inspired robotic devices. “We’re still teasing out why these species have evolved to run like this in the first place but, as we learn more, it’s clear that these lessons from nature may be able to be integrated into robotics,” he said.

“It’s been suggested that this movement might have something to do with increasing vision in moments of urgency, by elevating the head at the same time and helping to navigate over obstacles. Indeed, bipedalism would be advantageous for robots in specific habitats, for example, on open grasslands where, in nature, many bipedal running agamids are found.

“If obstacle negotiation is indeed improved with bipedal locomotion, then we have shown how the tail and body can be moved to enable it sooner and for longer. Maybe adding a tail to robots can help them go ‘off-road’ sooner.”