Study offers evidence that long countries give better protection to languages than those that are wide. One reason that Eurasian civilizations dominated the globe is because they came from a continent that was broader in an east–west direction than north–south, claimed geographer Jared Diamond in his famous 1997 book Guns, Germs and Steel. Now, a modelling study has found evidence to support this 'continental axis theory'.Continents that span narrower bands of latitude have less variation in climate, which means a set of plants and animals that are adapted to more similar conditions. That is an advantage, says Diamond, because it means...