Read More: Live Science
From the Abyssinian to the Turkish van, cat lineages have been bred for decades to produce felines with minor physical distinctions. These include rounder or leaner faces, shortened snouts, ears that fold inward, and coats in a variety of colors, textures and lengths. But the nuances among cat breeds pale in comparison to the staggering physical differences among pedigreed dogs. Corgis and dachshunds are short-legged and stumpy, with elongated, stocky bodies, while greyhounds and whippets are tall, lean and leggy. Mastiffs are short-haired bruisers that can weigh over 100 lbs. (45 kilograms) and have massive, powerful chests and jaws. Meanwhile, dainty Malteses and shih-tzus have long, flowing hair and can be carried in a handbag. Why don't pedigreed cats show the same extremes in body size and shape as dog breeds do? Currently, there are 42 recognized cat breeds in the U.S., according to the Cat Fanciers' Association (CFA). As for dogs, the American Kennel Club (AKC) recognizes 167 breeds, though the international organization Fédération Cynologique Internationale (FCI), also known as the World Canine Organization, acknowledges 340 dog breeds. In domesticated species, breeds represent lineages that were carefully monitored and manipulated over time through selective breeding to consistently produce animals with certain traits, Leslie Lyons, a professor with the College of Veterinary Medicine at the University of Missouri, told Live Science. New mutants Unexpected variations in the looks of an animal that's been bred — unusual size, lack of a tail, curly hair or peculiar markings, for example — are the result of genetic mutations, which appear naturally "all the time," and are then perpetuated through generations by people who find the new trait appealing, according to Lyons. "Even though the basic body plan says one thing, mutations occur, and humans select for the ones they prefer," she explained.