Dogs are Evolved from Wolves Through Artificial Selection

Take the domestic dog (Canis lupus familiaris), a single species that comes in all shapes, sizes, colors, and temperaments. Every single one, purebred or mutt, descends from a single ancestral species—most likely the Eurasian gray wolf—that humans began to select about 10,000 years ago. The American Kennel Club recognizes 150 different breeds, and you’ve seen many of them: the tiny, nervous Chihuahua, perhaps bred as a food animal by the Toltec of Mexico; the robust Saint Bernard, thick of fur and able to fetch kegs of brandy to snow-stranded travelers; the greyhound, bred for racing with long legs and a streamlined shape; the elongated, short-legged dachshund, ideal for catching badgers in their holes; retrievers, bred to fetch game from the water; and the fluffy Pomeranian, bred as a comforting lap dog. Breeders have virtually sculpted these dogs to their liking, changing the shade and thickness of their coat, the length and pointiness of their ears, the size and shape of their skeleton, the quirks of their behavior and temperament, and nearly everything else.

Jerry A. Coyne, Why Evolution Is True (January 22, 2009)

• breeding
• dogs
• evolution