Robot dogs are multiplying fast around the world, metamorphosing from amusing playthings to trusted companions deployed in a wide range of terrains from production plants to battlefields.
The growing use of the caninoids is part of a wider revolution in robotics, as advances in both hardware and software make the machines better able to adapt to difficult environments.
The mechanised quadrupeds hit a sweet spot by being both useful and predictable. They share crucial attributes with androids such as being able to walk. But their lower centre of gravity means they suffer less from problems, such as instability on rough ground, that have held back efforts to roll out two-legged robots.