Masticophis flagellum
Western coachwhip (M. f. testaceus), Santa Fe, New Mexico
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Masticophis
Species:	M. flagellum
Binomial name
Masticophis flagellum (Shaw, 1802)
Synonyms[2]
Coluber flagellum Shaw, 1802 Psammophis flagelliformis Holbrook, 1842 Herpetodryas flagelliformis — A.M.C. Duméril & Bibron, 1854 Zamenis flagelliformis — Boulenger, 1893 Bascanion flagellum — Lönnberg, 1894 Masticophis flagellum — Taylor, 1938 Coluber flagellum — Utiger et al., 2005 Coluber flagellum — Liner, 2007 Masticophis flagellum — Collins & Taggart, 2009

Masticophis flagellum is a species of nonvenomous colubrid snake, commonly referred to as the coachwhip or the whip snake, which is endemic to the United States and Mexico. Six subspecies are recognized, including the nominotypical subspecies.

The generic name, Masticophis, is derived from Greek mastix, meaning "whip", and ophis, meaning "snake", in reference to the braided appearance of the tail.^[3] The subspecific name, ruddocki, is in honor of Dr. John C. Ruddock who was medical director for the Richfield Oil Corporation.^[4]

Six subspecies of Masticophis flagellum are recognized as being valid, including the nominotypical subspecies.^[2]

Image	Species	Common Name
	M. f. cingulum Lowe & Woodin, 1954	Sonoran coachwhip
	M. f. flagellum (Shaw, 1802)	Eastern coachwhip
	M. f. lineatulus H.M. Smith, 1941	Lined coachwhip
	M. f. piceus (Cope, 1892)	Red coachwhip, red racer
	M. f. ruddocki Brattstrom & Warren, 1953	San Joaquin coachwhip
	M. f. testaceus (Say, 1823)	Western coachwhip

Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Masticophis.

Coachwhips are thin-bodied snakes with small heads and large eyes with round pupils. They vary greatly in color, but most reflect a proper camouflage for their natural habitat. M. f. testaceus is typically a shade of light brown with darker brown flecking, but in the western area of Texas, where the soil color is a shade of pink, the coachwhips are also pink in color. M. f. piceus was given its common name because specimens frequently, but not always, have some red in their coloration. Coachwhip scales are patterned so at first glance, the snake appears braided. Subspecies can be difficult to distinguish in areas where their ranges overlap. Adult sizes of 127–183 cm (50–72 in) in total length (including tail) are common. The record sized specimen, of the eastern coachwhip race, was 259 cm (102 in) in total length.^[5] Young specimens, mostly just over 100 cm (40 in) in length, were found to have weighed 180 to 675 g (6+1⁄2 to 24 oz), whereas good-sized mature adults measuring 163 to 235 cm (64 to 93 in) weighed 1.2 to 1.8 kg (2 lb 10 oz to 3 lb 15 oz).^[6][7]

Coachwhips range throughout the southern United States from coast to coast. They are also found in the northern half of Mexico.^[2][8]

Coachwhips are commonly found in open areas with sandy soil, open pine forests, old fields, and prairies. They thrive in sandhill scrub and coastal dunes. However, they prefer oak savannas in eastern Texas. ^[9]

Coachwhips are diurnal, and actively hunt and eat lizards, small birds, and rodents. They do not discriminate prey size, as they are opportunistic hunters.^[10] They have been described as "sit-and-wait" predators or ambush hunters.^[11] Coachwhips subdue prey by grasping and holding them with their jaws and do not use constriction.^[12] They tend to be sensitive to potential threats, and often bolt at the first sign of one, and will readily strike if cornered. Their bites can be painful, but generally are harmless unless they become infected, as is the case with any wound. They are curious snakes with good eyesight, and are sometimes seen raising their heads above the level of the grass or rocks to see what is around them. They are extremely fast-moving snakes, able to move up to 4 miles per hour.^[13]

The primary myth concerning coachwhips, that they chase people, likely arises from the snake and the person both being frightened, and both just happening to be going the same way to escape.^[14] Coachwhips are fast snakes, often moving faster than a human, and thus give an impression of aggression should they move toward the person.

The legend of the hoop snake may refer to the coachwhip snakes.

• 
  Head of an eastern coachwhip (Masticophis flagellum flagellum) Florida (14 September 2015)
• 
  Eastern coachwhip (Masticophis flagellum flagellum), St. Genevieve County, Missouri (13 April 2014)
• 
  Eastern coachwhip (Masticophis flagellum flagellum), Jefferson County, Missouri (9 September 2018)
• 
  Eastern coachwhip (Masticophis flagellum flagellum), Taney County, Missouri (11 April 2015)
• 
  Head of an eastern coachwhip (Masticophis flagellum flagellum) from the Ozarks, Missouri (3 March 2021)
• 
  Eastern coachwhip (Masticophis flagellum flagellum), Florida (14 February 2016)
• 
  A juvenile eastern coachwhip (Masticophis flagellum flagellum), Jefferson County, Missouri (31 March 2016)
• 
  Sonoran coachwhip (Masticophis flagellum cingulum), Nogales, Arizona (28 November 2010)
• 
  Red racer (Masticophis flagellum piceus), Joshua Tree National Park, California (29 April 2011)
• 
  Juvenile western coachwhip (Masticophis flagellum testaceus).

Wikimedia Commons has media related to Masticophis flagellum.

• "Common Snake Myths". Austin Reptile Service.
• "The Red Coachwhip".

• Behler, John L.; King, F. Wayne (1979). The Audubon Society Field Guide to North American Reptiles and Amphibians. New York: Alfred A. Knopf. 743 pp., 657 plates. ISBN 0-394-50824-6. (Masticophis flagellum, pp. 328–329 + Plates 469, 491, 553–554, 556, 558).
• Boulenger GA (1893). Catalogue of the Snakes in the British Museum (Natural History). Volume I., Containing the Families ... Colubridæ Aglyphæ, part. London: Trustees of the British Museum (Natural History). (Taylor and Francis Printers). xiii + 448 pp. + Plates I-XXVIII. (Zamenis flagelliformis, pp. 389–390).
• Conant, Roger; Bridges, William (1939). What Snake Is That? A Field Guide to the Snakes of the United States East of the Rocky Mountains. (With 108 drawings by Edmond Malnate). New York and London: D. Appleton-Century Company. Frontispiece map + 163 pp. + Plates A-C, 1-32. (Masticophis flagellum, pp. 47–50 + Plate 6, figures 17–18).
• Goin, Coleman J.; Goin, Olive B.; Zug, George R. (1978). Introduction to Herpetology, Third Edition. San Francisco: W.H. Freeman and Company. xi + 378 pp. ISBN 0-7167-0020-4. (Masticophis flagellum, p. 129).
• Schmidt, Karl P.; Davis, D. Dwight (1941). Field Book of Snakes of the United States and Canada. New York: G.P. Putnam's Sons. 365 pp., 34 plates, 103 figures. (Coluber flagellum, pp. 127–131 + Figure 29 on p. 122 + Plate 13).
• Shaw G (1802). General Zoology, or Systematic Natural History, Vol. III., Part II. London: G. Kearsley. vii + pp. 313–615. (Coluber flagellum, new species, p. 475).
• Smith, Hobart M.; Brodie, Edmund D., Jr. (1982). Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN 0-307-13666-3 (paperback), ISBN 0-307-47009-1 (hardcover). (Masticophis flagellum, pp. 192–193).
• Wright, Albert Hazen; Wright, Anna Allen (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Associates, a division of Cornell University Press. 1,105 pp. (in two volumes). (Masticophis flagellum, pp. 432–450, Figures 130–133, Map 37).