What it is
A walking robot built to copy Orobates, an animal that lived about 294 million years ago. Scientists in Switzerland and Germany built it from the fossil's bones: the length of each part, the weight of each part, and where the animal's balance point sat.
Inside it
Twenty-eight motors drive it: eight along the spine, four in each leg, and four smaller ones. It is 1.6 times the size of the fossil, about one and a third meters long, and weighs about six kilograms. Its tail is held clear of the ground, because the fossil trackways show no sign of a dragging tail.
What it showed
First a computer tried 512 ways the animal could have walked and threw out the ones that wobbled, wasted power, or missed the footprints. The robot then walked 15 of those gaits along a scaled copy of a real fossil trackway. The walks that passed held the body high, off the ground. That is closer to a caiman than to a salamander.
Where it came from
OroBOT was built on an earlier robot, Pleurobot, which was made to copy the walk of a living newt, filmed with x-rays.