Leafcutter ants, a non-generic name, are any of 47 species of leaf-chewing ants. Next to humans, leafcutter ants form the largest and most complex animal societies on Earth. In a few years, the central mound of their underground nests can grow to more than 98 feet across and contain eight million individuals. The ants cultivate specific fungus in their colony as food, requiring them to bring in different vegetation to farm their fungus.