Often, when a child or even an adult is dirty, people call him a pig or compare him to a pig. There is no reason to use an animal's name as an insult. In facts, pigs actually like it when they are clean. However, because it has no arms, it has to find its own way to take baths. The only water it has is the closest puddle and some mud and grass is its natural scrubby loofah. These baths are what keeps the pigs clean.

However, that is not the only reason. The mud protects them from flies and insects that sometimes get stuck on their skin. After the bath, a pig is covered in a thin layer which removes bugs that might be stuck in the skin and keeps away the new ones.