Drymarchon melanurus erebennus

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.

Drymarchon melanurus erebennus
Texas indigo snake
Conservation status
Apparently Secure (NatureServe)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Drymarchon
Species:	D. melanurus
Subspecies:	D. m. erebennus
Trinomial name
Drymarchon melanurus erebennus (Cope, 1860)
Synonyms
Spilotes erebennus Cope, 1860 Drymarchon corais erebennus — Taylor, 1949 Drymarchon melanurus erebennus — Wüster et al., 2001

Geographic range

D. m. erebennus is found from South Texas south into Mexico as far as Veracruz.

Description

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 6 ft (1.8 m). Specimens 8 ft (2.4 m) long are not unheard of.

Habitat

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.

Behavior and diet

D. m. erebennus is diurnal and spends most of its time actively hiding. It consumes almost any prey 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 South Texas consider it a useful ally, hence the adage, "If it's an indigo, let it go." It is a defensive snake, but may bite or release a foul-smelling musk from its cloaca if handled or harassed. Like many colubrid snakes, it often shakes its tail as a warning, though it does not possess a rattle.

Reproduction

Breeding of D. m. erebennus takes place, generally yearly, in the winter. Clutches of typically 10–12 eggs are laid in the spring, and hatch around 80 days later. Hatchlings can be up to 26 in (66 cm) long. Maturity is reached in 2–3 years.

Conservation

The Texas indigo snake is listed as a threatened species by the state of Texas. 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.

Further reading

• Werler, John E.; Dixon, James R. (2000). Texas snakes: Identification, Distribution, and Natural History. Austin, Texas: University of Texas Press. 522 pp. ISBN 978-0292791305. (Texas indigo snake, pp. 98–102).
• Crother BI, Boundy J, Campbell JA, de Quieroz K, Frost D, Green DM, Highton R, et al. (2003). "Scientific and standard English names of amphibians and reptiles of North America north of Mexico: Update". Herpetological Review 34: 196–203.