Formica rufa, commonly known as the red wood ant, is a species of ant found primarily in forests across Europe and parts of Asia. These ants are known for their reddish-brown color and can grow up to 1 cm in length. They build large nests made of twigs, leaves, and soil, often found at the base of trees. These ants play a crucial role in their ecosystem by aerating the soil and controlling pest populations. Formica rufa is also known for its aggressive behavior when defending its nest, using formic acid as a defense mechanism against predators.