From ancient Egyptians to today’s internet users, people have always loved their cats. In the U.S. alone, cats reign over about 45.3 million households. There are at least 45 domestic breeds, which differ widely in features such as coat color, tail length, hair texture, and temperament, according to the Cat Fancier’s Association. The Maine Coon is the largest, with males reaching an average of 3.5 feet long. The smallest breed is the Singapura, native to Singapore, with adult females weighing as little as four pounds. One of the most unusual-looking cats is the Sphynx, a mostly hairless cat known for being robust and intelligent.