Hundreds of millions of years ago, when dinosaurs ruled the earth, a small group of ancient nocturnal reptiles unwittingly found a survival strategy that led to the evolution of the brain
Many early mammals evolved smaller bodies by natural selection, while their brains failed to shrink to scale.
 The development of a sense of smell drove the evolution of ancient reptile brains, scientists have concluded from the fossilized skulls of reptiles that closely resemble primitive mammals