However, most Earth scientists and palaeontologists did not believe Wegener's theory and thought it was foolish. Some critics thought that giant land bridges could explain the similarities among fossils in South America and Africa. Others argued that Wegener's theory did not explain the forces that would have been needed to move continents to such great distances. Wegener thought that the forces that moved the continents could be caused by the rotation of the Earth and stellar precession and that same forces made earthquakes and volcanic eruptions.