Wild peanuts evolved about the same time as other flowering plants, about 350 million years ago. They’re a low-growing shrub like other South American plants such as potatoes or tomatoes. But they’re not related to potatoes or tomatoes. Instead, peanuts are a legume, related to lentils and pinto beans. Peanuts like dry, warm, sandy soil.
People probably first began to eat wild peanuts as soon as they arrived in South America, about 13,000 years ago. Peanuts have a lot of protein and fat. But wild peanuts don’t make a lot of peanuts to eat. By around 6000 BC, people were farming peanuts in river valleys in southern Bolivia (in central South America). Farmers bred the peanut plants to make more peanuts on each plant.
When European traders started sailing to Brazil and Peru about 1500 AD, they brought peanuts to Asia, Europe, and Africa. The Spanish word for peanut comes from the Aztec word cacahuatl. Slave traders fed enslaved Africans peanut sauces on rice or corn because they were cheap. Peanuts were a lot like the native African groundnuts, and soon a lot of Africans switched from groundnuts to peanuts.
Indian traders brought peanuts from Africa to India in the 1600s, and European traders brought peanuts (along with sweet potatoes) to Southeast Asia and southern China about the same time. Many Thai recipes also began to include peanut sauce.
During the American Civil War, people in the south couldn’t get a lot of foods because the Union Army was blockading them. They had plenty of peanuts, though, so they used peanut oil instead of whale oil and olive oil, and they ate peanut brittle instead of chocolate. Union soldiers also ate a lot of peanuts while they were fighting in the South, and after the Civil War peanuts were the cool thing to eat all over the United States.
After 1890, machines harvested and shelled peanuts, and they became much cheaper. In 1916, the African-American food scientist George Washington Carver popularized peanut butter, and that quickly got to be a favorite American food too. Carver encouraged Southern farmers to switch to growing peanuts instead of cotton. But all over the world, the biggest use of peanuts today – and the reason China produces most of the world’s peanuts – isn’t even about eating actual peanuts. Most of the world’s peanuts today to go make peanut oil.