Cochineals are tiny bugs that live on prickly pear cactuses. The acid in their guts makes a red dye used in textiles, cosmetics, and foods like M&Ms and Yoplait yogurt. Indigenous people across Latin America traded it for thousands of years. It can be found on the walls of archeological sites, in priceless paintings, and in the robes of kings. But today, Peru dominates the market, and Mexico’s cochineal farms are disappearing. We met a few of the country’s last farmers trying to keep the ancient