Swine, commonly known as pig, has always been an integral part of human lives. It was domesticated over 6,000 years ago and it has become a main part of our staple food ever since.Pig looks fat, dumb and dirty, but there are justifications. Pigs are often covered in mud because it helps to keep them cool. They eat everything they could find in order to survive. Contrary to the common stereotype, pigs are not dumb. In fact, they are highly intelligent. They are even smarter than dogs.Pig means more than just food on our dinner table. It is much more valuable to humans than many people give it credit for. Insulin used to treat diabetic patients is made from pig insulin, so are many medicines also made from pig. In the future, swine organs may be able to substitute human organs in organ transplants, because of their similarities in size, weight and function with human organs.We always say that dogs are man's best friends. As you can see, pigs, in many ways, are indispensable to man.