Masticophis flagellum

Masticophis flagellum is a species of nonvenomous colubrid snake, commonly referred to as the coachwhip, whip snake or the red racer. It is endemic to the United States and Mexico. Six subspecies are recognized. It is listed as a species of Least Concern by the ICUN.

Taxonomy

Etymology

Masticophis is derived from the Greek words mastix, meaning "whip", and ophis, meaning "serpent". Flagellum is Latin for "whip". The scientific name was given due to the braided, whip-like appearance of the tail coupled with the length of the snake. Subspecific translations are as follows: cingulum, Latin for "belt or girdle". Liniatula, Latin for "line". Piceus is Latin for "pitch-dark", here in reference to the color of the snake. Ruddocki refers to Dr. John C. Ruddock, a medical doctor and pioneer in laparoscopy in the 1930s. Testaceus is Latin for "hard covering made of brick or tile", in reference to the scaling pattern of the snake.

Subspecies

Including the nominotypical subspecies, there are six subspecies of Masticophis flagellum. Scientific and common names are listed below.

Image	Species	Common name
	M. f. cingulum Lowe & Woodin, 1954	Sonoran coachwhip
	M. f. flagellum	Eastern coachwhip
	M. f. lineatulus H.M. Smith, 1941	Lined coachwhip
	M. f. piceus	Red coachwhip, red racer
	M. f. ruddocki Brattstrom & Warren, 1953	San Joaquin Coachwhip
	M. f. testaceus	Western coachwhip
	M. f. fuliginosus	Baja California Coachwhip

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

Description

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 in total length are common. The record sized specimen, of the eastern coachwhip race, was in total length. Young specimens, mostly just over in length, were found to have weighed, whereas good-sized mature adults measuring weighed.

Distribution and habitat

Coachwhips range throughout the southern United States from coast to coast. They are also found in the northern half of Mexico.
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.
Coachwhips have been found to tolerate isolated, buffered habitat fragments; however, habitat configuration and edge exposure may be factors which can negatively influence the viability of habitat use by this sensitive species.

Behavior

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 periscoping, 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. Coachwhips have also been found to adjust their space-use behavior with changes in habitat fragment size, tolerating more crowded conditions, reduced home-range sizes, and increased home-range overlap when available habitat area decreased.

Feeding

Coachwhips are diurnal, and actively eat different types of prey including other snakes, lizards, frogs, rodents, birds, and insects. These snakes have also been found to ingest carrion and, in rare instances, demonstrated cannibalism. They do not discriminate prey size, as they are opportunistic hunters. They have been described as "sit-and-wait" predators or ambush hunters. They utilize both enhanced vision and sensitive chemoreceptors in order to detect nearby prey. Coachwhips subdue prey by grasping and holding them with their jaws and do not use constriction.

Myths

A few myths are associated with the coachwhip snake: that they deliberately chase people and whip them with their tails, that they suckle milk from farm animals, and are the legendary "hoop snakes". None of these are true.