the eastern indigo snake has a blue-black colour. it is the longest native snake species in the united states. males usually grow up to 1.58 m (5.2 ft) in length. females usually grow up to 1.38 m (4.5 ft) in length. males usually weigh 2.2 kg (4.9 lb). females usually weigh 1.5 kg (3.3 lb).