Roomboos is the name applied to large, fossorial and semi-aquatic creatures native to the planet Mars. They appear to be a mammalian species, but have six legs in total. It's believed that they are the creatures responsible for digging the famous Martian canals observed by Percival Lowell and other astronomers. However, the Roomboos are not sapient, and seem to have been domesticated by the Erloors.