Drymarchon Corais Couperi, commonly known as the eastern indigo snake, is a species of non-venomous snake found in southeastern United States. Also known as the blue indigo snake or the Carolina pine snake, it is the longest snake native to the United States. The name "indigo" refers to the snake's glossy, iridescent blue-black color. In addition to its scientific name, the eastern indigo snake has several synonyms, including the blue racer, the black bull snake, the indigo bull snake, and the Indian black snake. Despite its similar appearance to venomous snakes, the eastern indigo snake is harmless and plays an important role in its ecosystem as a predator of small animals, such as rodents and frogs.