Maine Coon cat. Maine Coons are one of the largest breeds of domestic cat. Males weigh from 15 to 25 lb (6.8 to 11 kg) with females weighing from 10 to 15 lb (4.5 to 6.8 kg). In 2010, the Guinness World Records accepted a male purebred Maine Coon named "Stewie" as the "Longest Cat" measuring 48.5 in (123 cm) from the tip of his nose to the tip of his tail. It's a freaking dog in a cat suit.