“In nature—out yonder where the crawdads sing—these ruthless-seeming behaviors actually increase the mother’s number of young over her lifetime, and thus her genes for abandoning offspring in times of stress are passed on to the next generation. And on and on. It happens in humans, too. Some behaviors that seem harsh to us now ensured the survival of early man in whatever swamp he was in at the time. Without them, we wouldn’t be here. We still store those instincts in our genes, and they express themselves when certain circumstances prevail. Some parts of us will always be what we were, what we had to be to survive—way back yonder.”

Where the Crawdads Sing by Delia Owens