Pig

The pig is a farm animal raised all over the world for its meat. Pigs also live in the wild, where they are called wild boars. A fully grown farm pig can weigh between 300 and 700 pounds, about as much as a small motorcycle. Pigs belong to a group of mammals called Sus, and they have lived alongside humans for at least 9,000 years.

Pigs have stocky bodies, short legs, and a flat snout they use to dig in the ground. Each foot has four toes, but pigs walk on just the middle two. Their skin is covered in coarse hair called bristles. Most farm pigs are pink, but wild pigs are usually brown, gray, or black. A pig's tail is often curly, though some breeds have straight tails.

Pigs will eat almost anything. They eat plants, roots, fruits, nuts, insects, and even small animals. Farmers often feed them grain mixed with leftover food scraps. A pig's snout is one of the most powerful noses in the animal world. Pigs use it to sniff out roots and mushrooms buried deep underground. In parts of France and Italy, farmers train pigs to find truffles, a kind of rare mushroom that can sell for hundreds of dollars a pound.

People often use "pig" as an insult for being dirty or greedy, but this is not fair. Pigs are actually very clean animals when they have enough space. They pick one spot far from where they sleep to use as a bathroom. They also roll in mud, but not because they like being dirty. Pigs cannot sweat, so mud keeps them cool on hot days.

Pigs are also smart. Scientists who study animal minds rank pigs among the most intelligent farm animals, close to dogs in many tests. Pigs can learn their names, solve simple puzzles, and even play video games with a joystick made for their snouts. They use at least 20 different sounds to talk to each other. Mother pigs sing to their piglets while nursing them.

All farm pigs came from the wild boar, which still lives across Europe, Asia, and North Africa. People first tamed wild boars in both China and the Middle East around 7000 BCE. Today there are more than 700 million farm pigs on Earth. China raises about half of them. In the United States, Iowa alone has more pigs than people.

Wild pigs have also become a big problem in parts of the world where they do not belong. In the southern United States, millions of feral pigs, descended from escaped farm pigs, now damage crops and forests.