A pig is a smart, social farm animal with a stout body, short legs, a flat snout, and a curly tail. Pigs are omnivores, meaning they eat both plants and other foods, and they're remarkably intelligent: studies show they can solve puzzles, learn tricks, and recognize themselves in mirrors. Despite their reputation for being dirty, pigs are actually quite clean when given proper space. They roll in mud to cool off since they can't sweat.

Farmers raise pigs for meat, which is called pork. Products like bacon, ham, and sausage all come from pigs. Pigs have been domesticated for about 9,000 years and are raised on farms worldwide.

The word pig also describes someone who eats greedily or messily, though this isn't really fair to actual pigs. If your brother devours his entire plate and reaches for seconds before anyone else has been served, someone might say he's pigging out or being piggish. People also use pig as an insult for someone who's selfish or messy, like a person who refuses to share or leaves their belongings scattered everywhere.

Guinea pigs, despite their name, aren't pigs at all. They're small rodents from South America that are popular pets.