The animal known to have the largest brain relative to its body size is the ant. Despite their small size, ants possess a brain that is proportionally larger than those of many mammals. This exceptional brain-to-body ratio allows them to perform complex tasks such as navigation, communication, and problem-solving. Ants exhibit remarkable social behaviors and cooperation within colonies, showcasing their intelligence and adaptability. Studying the cognitive abilities of ants can provide insights into the evolution of intelligence across species.