Last week, Nasa announced that it is developing robotic bees to gather information about areas of Mars that wouldn't be accessible to a Mars rover. The bots could detect, for example, methane, a possible sign of life. Boston Dynamics' latest robot resembles a dog with an arm where its head should be. It recently demonstrated it can use the arm for the complex (in robot terms) action of opening a door, despite the intervention of man with a hockey stick. Its fins are flexible, giving it the ability to glide through turbulent seas. The team hopes that the bot could prove useful for underwater searches and gathering marine data.