There are many different breeds of cats, including Abyssinian, Himalayan, Maine Coon, Manx, Persian, Scottish Fold, and Siamese, to name a few. The Cat Fanciers’ Association, which is the world’s largest registry of pedigreed cats, recognizes about 40 distinct breeds. The most familiar cats are the domestic shorthair and the domestic longhair, which are really mixtures of different breeds. Cat breeds differ in looks, coat length, and other characteristics but vary relatively little in size. On average, only 5 to 10 pounds separate the smallest and largest domestic breeds of cats. Cats also share the rapid metabolism that dogs have, which results in a higher heart rate, respiratory rate, and temperature than those of people. Cats generally live longer than dogs, and many live to be 20 years old or older. Cats are better at conserving heat than at cooling themselves, although their small size relative to their large surface area makes for more effective cooling than in dogs. Cats lose heat through external radiation. They have some sweat glands that aid in evaporative cooling, and licking their fur further improves this process. Heat is also lost through panting, although this is not as effective a method of cooling as it is in dogs. Cats typically also seek dark, cool places to shelter themselves from the heat of the day. As with all animals, cats should never be shut in cars or other hot, confined spaces. This can lead to heat stroke and death. The muscles, tendons, joints, ligaments, and spine of cats are extremely flexible, making them agile hunters. Cats can walk, run, leap, twist, and even roll into a ball. They can leap long distances and twist in mid-air to obtain a better angle of attack. The feline bones that are comparable to the long bones of our hands and feet are located in the cat’s lower legs. The angular hock in the hind legs is comparable to the ankle in people. Their normal gait is a “pace,” in which both legs on one side move together.