Most dung beetles search for dung using their sensitive sense of smell. Some of the smaller species simply attach themselves to the dung-providers to wait for their reward. After capturing the dung, a dung beetle will roll it, following a straight line despite all obstacles. Sometimes dung beetles will try to steal the dung ball from another beetle, so the dung beetles have to move rapidly away from a dung pile once they have rolled their ball to prevent it from being stolen. Dung beetles can roll up to 50 times their weight. Male "Onthophagus taurus" beetles can pull 1,141 times their own body weight: the equivalent of an average person pulling six double-decker buses full of people. In 2003, researchers found one species of dung beetle (the African "Scarabaeus zambesianus") navigates by using polarization patterns in moonlight. The discovery is the first proof any animal can use polarized moonlight for orientation. 