Length: (1/11″ -1/10″. These medium sized ants are uniformly brown and trail in large numbers. They compete aggressively with other ant species for food and nesting sites and can drive most other ant species out of their territory. Their nests have large numbers of individuals and a high percentage of queens. Because of their aggressive nature, these ants will develop into super-colonies in many urban situations with the colony spread across large areas. It is not uncommon to find Argentine ants spread across entire neighborhoods. Their nests are often under heavy leaf litter, under wood on the ground, at the base of trees and in planters and mulch. They prefer the outdoors, but will enter houses looking for food, water and warmth. They particularly like sweet foods.