In recent months we have heard a suggestion that the Neanderthal’s extinction, 28,000 years ago, may have been hastened by the evolutionary cost of their bigger eyes, necessary for hunting in the dim northern European light, at the expense of extra brainpower to cope with the coming ice-age changes. Homo sapiens backed the right horse and used that brain power to evolve light sources for their surroundings, using in turn, oil lamps, candles, gas and kerosene lamps then electricity.