Why do elephants have long big ears?

African elephants live in a hotter climate than indian or asian elephants. Since elephants don't sweat they flap their ears to cool the blood vessels down as much as 10

degrees.
The Asian elephant has smaller ears because in Asia there are more trees to keep shade but in Africa there are less trees so the African elephant has to keep cool by swaying his or her ears back and forth to make a breeze.