Why do elephants have big ears? (size, surface area, volume?)?

If a scale model of you was built twice as tall as you, it would have 4 times your surface area to get rid of excess heat but 8 times the volume of muscle and brain producing heat, so large animals like elephants need ways of shedding heat that you haven't got, like large ears and panting, like dogs do, especially as many of these animals, such as jumbos, live in the tropics. A beached whale, being large, is likely to die of heart failure. Animals as large as whales need to live in the water, so buoyancy can support them. Because of the scaling thing, large animals, which produce large amounts of heat, are happier in cooler climates. Similarly small people are more likely to come down with hypothermia. People like Europeans and Inuit tend to be fatter than black people and south east Asians. Robins in Iceland are about as big as thrushes in the south of England. This scaling thing explains why no animals larger than hummingbirds can use the same method to fly, and planes can't fly like geese do, by flapping their wings. As you get bigger the lift you get goes up as the square of your length, but the weight to be lifted goes up as the cube.