Drymarchon melanurus erebennus, commonly known as the Texas indigo snake, is a subspecies of large, nonvenomous snake in the family Colubridae. The subspecies is native to Texas in the United States and adjacent Mexico.
D. m. erebennus is found from southern Texas south into Mexico as far as Veracruz.
Dorsally, the Texas indigo snake is predominantly black in color, with a high sheen which gives its smooth scales a remarkable iridescent hue. The underside is often a salmon pink color. It is a large snake, regularly attaining a total length (including tail) beyond 6feet. Specimens 8feet long are not unheard of.
The Texas indigo snake prefers lightly vegetated areas not far from permanent water sources, but is also found in mesquite savannah, open grassland areas, and coastal sand dunes. It dens in burrows left by other animals.
D. m. erebennus is diurnal, and spend most of its time actively hiding. It will consume almost anything it can overpower and swallow, including mammals, birds, lizards, frogs, turtles, eggs, and even other snakes, including rattlesnakes. Because of its aggressive attacks on rattlesnakes, many farmers in southern Texas consider it a useful ally.[1] Hence the adage, "If it's an indigo, let it go." It is not a typically aggressive snake, but may bite or release a foul smelling musk from its cloaca if handled or harassed. Like many colubrid snakes, it will often shake its tail as a warning – even though it does not possess a rattle.[2]
Breeding of D. m. erebennus takes place, generally yearly, in the winter. Clutches that average 10–12 eggs are laid in the spring, and hatch around 80 days later. Hatchlings can be up to 26inches long. Maturity is reached in 2–3 years.
The Texas indigo snake is listed as a threatened species by the state of Texas.[3] Its primary threat is from habitat loss due to human development. Each snake requires a large home range to forage, and urban sprawl is shrinking its usable habitat. Roads bisect its territory, and many snakes each year are run over by cars.