The eastern indigo snake (Drymarchon couperi) is a species of large, non-venomous snake in the family Colubridae. Native to the southeastern region of the United States, it is the longest native snake species in North America. The eastern indigo snake has uniform blue-black dorsal scales, with some specimens having a reddish-orange to tan color on the throat, cheeks, and chin. This snake received its common name from the glossy iridescent dorsal and ventral scales which can be seen as blackish-purple in bright light. This smooth-scaled snake is considered to be the longest native snake species in the United States and all of North America. The longest recorded specimen measured 2.8 m (9.2 ft) in total length (including tail). Unlike many snakes, mature male indigo snakes are slightly larger than females. This is thought to be due to intraspecies competition and combat with the males. A typical mature male measures 1.2–2.36 m (3.9–7.7 ft) in total length, with a reported average of 1.58 m (5.2 ft), and weighs 0.72–4.5 kg (1.6–9.9 lb), reportedly averaging 2.2 kg (4.9 lb). Meanwhile, a mature female typically measures around 1.1–2 m (3.6–6.6 ft) in total length, averaging 1.38 m (4.5 ft), and weighs 0.55–2.7 kg (1.2–6.0 lb), averaging 1.5 kg (3.3 lb). Specimens over 2.6 m (8.5 ft) can weigh up to 5 kg (11 lb). Although the eastern indigo snake is similar in average body mass, extremely large specimens of the bulky, co-occurring venomous eastern diamondback rattlesnake can outweigh it. (Source: Wikipedia.org, CC BY-SA)