Those who have encounters with coachwhips do not soon forget them.  These long, slender snakes are a blur of motion as they streak across the ground.  Herpetologists or naturalists impetuous enough to want to catch one often dive through greenbriars and brush only to come up empty-handed.  If you do catch one, there is the discomfort and indignity of having it repeatedly bite you, with rows of small sharp teeth (but no venom).  Coachwhips are a favorite of mine partly because of their big, alert eyes and the impression of intelligence they convey.  They seem to be the hawks of the snake world in their reliance on vision and their bright, scowling eyes.  This is an ironic connection, since coachwhips big snakes that tend to forage in the open during the daytime are frequently preyed upon by hawks.
The coachwhip clan
        Coachwhips and their relatives are found in the U.S. from coast to coast.  The eastern coachwhip (Masticophis flagellum flagellum1) occupies a variety of habitats from North Carolina through the American Southeast and westward to eastern Texas, Oklahoma, and Kansas.  At that boundary, the western coachwhip (Masticophis flagellum testaceus) takes over, extending through the rest of Texas and into surrounding areas of Mexico, New Mexico, Colorado, and western Oklahoma, Kansas, and a bit of Nebraska.  Westward from the western coachwhip's range, there are other coachwhip subspecies, principally the red coachwhip.
Other closely related species are the various whipsnakes (Masticophis taeniatus, M. lateralis, and M. bilineatus), very slender and exceedingly active snakes generally adapted to hot and relatively dry habitats.  Four subspecies of whipsnakes occur in Texas, and others are found west and north of Texas toward the Pacific coast.  One subspecies, the Alameda whipsnake (M. l. euryxanthus), occurs along part of the California coast.  This endangered snake has been at the center of a conservation struggle for some time, as developers seek to build houses on its habitat.
        Recent scientific work has resulted in a revision of the status of the coachwhips and whipsnakes (Masticophis) so that they would be placed in the genus Coluber, with the racers.  There is still some debate on the matter, but in the future, these snakes may be considered a species of Coluber.
Description of the western coachwhip
        This snake commonly reaches 4 to 5½ feet in length (the record is 6 feet, 8 inches).  The scales are large and smooth on the snake's back and sides.  Some snakes have proportionally smaller scales, and counting them up one side, across the back, and down the other may result in, say 27 rows of scales (this is true of the Texas rat snake, another large harmless snake).  The coachwhip is not only slender, but has large dorsal scales, and so it has only 17 rows on the forebody.  They are also dark-edged, particularly toward the tail, giving the tail a visual texture that looks like a braided whip. 
        For the most part, this is a plain tan or reddish-brown snake, with some variations.  The most common form is a light tan or sandy color with numerous darker, narrow partial crossbands indistinctly scattered along the snake's back.2  Another pattern variation consists of alternating very broad darker and lighter bands.  Each band may run 10 to 15 scales from front to back and the amount of contrast between light and dark bands is variable from one snake to another.  Also, while coachwhips in central Texas may have rusty reddish heads and necks, some west Texas and Big Bend individuals may be brick red to pinkish in color.  The underside of the neck and forebody generally has a double row of reddish spots, giving the impression of a double line extending down the neck and fading out further back.
        Juveniles, approximately 10-15 inches long, are light brown with fairly distinct narrow crossbars of darker brown on the forward part of the body.  Their heads are particularly striking, with the large scales have white leading edges, and with trailing edges dark brown.  The pattern on the belly scales tends also to be brighter and more distinct than is the case with adults.
        The eyes are large and round, with the scale above the eye (the supraocular) forming a ridge like an eyebrow and giving the eyes a stern appearance.  The overall impression you get is that of an intelligent, visually alert and determined predator.  It is often misleading to make assumptions about behavioral qualities based on the appearance of the face, as reptiles cannot move the parts of their faces to express anything.  However, as seen below, those inferences about "stern" behavior are not far off the mark.
        Where do they live?
        These snakes tend to be habitat generalists, able to make use of a fairly broad assortment of relatively dry habitats.  Writing in 1957, Wright and Wright3 said that western coachwhips were frequently found in pastures and fields.  They wrote:  "Far more records, however, are from the roadsides or roads, where they are frequently killed by the auto.  Other habitats are sunny hillsides; open woods; along a river or river bottom; semibrushy areas; dry rocky situations; rock ledges."
In the different ecological areas or biotic provinces of Texas, western coachwhips may be found in desert scrub, grassy plains, coastal prairies, and rocky areas of the Edwards Plateau.  In north Texas, coachwhips have been found in savannahs and open areas of the cross timbers woodlands, and remnants of tallgrass prairie or disturbed prairie. 
        Abundance
        Some consider this snake to be among the most common large, nonvenomous snakes throughout its Texas range. 4  The ability to make use of a variety of habitats, including disturbed areas, works in its favor.  Not seeing a coachwhip in the field may not be an indication that the species is not found there.  Patterned inconspicuously and active during the day, the coachwhip may see you and move out of the area before you see it.
        Food
        Lizards, small mammals, large insects such as grasshoppers and cicadas, birds and their eggs, and other snakes may be consumed.  For juveniles, insects may be a primary food source.  Tennant and Bartlett cite investigations showing that hatchlings have an inborn feeding response to the scents of lizards and snakes found in their area. 
Behavior
        These snakes may make use of burrows or other shelter at night, and then bask in the morning to get their temperature up before foraging.  They are able to withstand high temperatures, gliding around in the open for a few minutes at a time even when temperatures are around 100°F and then staying in the shade long enough to keep from overheating.  Werler & Dixon cite a report indicating that the coachwhip's heat tolerance is about 108°F.  (If you capture one, do not take its heat tolerance for granted.  A coachwhip may survive on a hot day by being able to move to cooler areas whenever it needs to.  A snake in a bag will rapidly overheat in a hot car or when exposed to the sun.)
        The coachwhip's "job" its ecological niche involves high activity, speed, and sight-hunting.  The snake may cruise around with head held high, turning to look in different directions for prey.  Its eyesight may also be important for spotting and avoiding hawks, which are major predators of coachwhips.  As they look for prey, they may cover a large area.  Werler & Dixon note that the activity range of a western subspecies, the red coachwhip, may be 145 acres.  When they catch a lizard or grasshopper, they do not constrict but hold the prey item against the ground with their heads and powerful jaws while preparing to swallow it. 
While coachwhips seem incredibly fast, they are actually not able to move as fast as a person can run.  What they are able to do is to change direction without slowing and thread their way through rocks and thickets where humans can go only with difficulty.  For naturalists and collectors, this results in many mishaps and much colorful language.  In the Trans-Pecos area of Texas in May of 2002, a group of us stopped for a big red coachwhip that had been on the road and then shot into the nearby vegetation.  Knowing that all vegetation in west Texas is sharp-pointed, thorny, or otherwise capable of inflicting pain, I declined to dive in.  Seeing another one near the Pecos River a short while later, one of our group did make a grab for it, and may still be picking cactus spines from his body. 
        They are fast, but not faster than cars.  I remember seeing coachwhips in sand dunes and grassy areas on Padre Island in the 1960s.  Driving along, we would see a shimmer across the road ahead; not the usual heat shimmer but a horizontal serpentine motion as a coachwhip shot across the road.  Of course, they often lost the race with cars and they are frequently found as roadkills in rural areas all over Texas.
        The coachwhip's defensive biting is well-known.  Although they make every effort to get away from humans, if picked up they usually strike very aggressively, and may target the face and eyes.  They bite and pull away, leaving small scratches and tears in the skin.  Once calmed somewhat, they may sit quietly in the hand but will take advantage of an opportunity for escape, bolting unexpectedly out of the handler's grasp.  There are also some reports of death-feigning in coachwhips grabbed by humans, going limp with mouth open after a period of struggle.
One spring day southwest of San Angelo, a group of us witnessed how bold these snakes when they go "a-courtin'."  We spotted one nearby in some rocks, and it had seen us, too.  However, it did not take off in the opposite direction.  As we continued to look carefully, we noticed that a different coachwhip was within the rock pile beside the first one.  The story became clear: the snake we had first seen was a male, and he was not going to lose the opportunity with this female just because some people were nearby.  (If you look at the photo on the cover, in the upper left a part of the female's body can be seen.)
        Tall tales
        Snakes are the subject of many tall tales and legends, and the coachwhip's resemblance to a whip suggests the kind of tall tale you might hear.  Sure enough, rural folks tell of the snake that chases you down and whips you.  How severe the "whippin'" is something that depends on the teller.  Needless to say, the story is not true.  It is possible that such tales were inspired by the fact that, when grabbed, coachwhips flail and thrash about.  Similarly, a snake that has just been hit by a farmer's hoe or a stick may thrash as it dies, suggesting a whipping motion.
Reproduction
        Coachwhips lay eggs with granular surfaces, similar to those of racers.  After mating in April or May, the female chooses a suitable site for egg-laying.  This may be in loose soil or a decaying log or other moist area.  Hatching occurs in late summer, after about 6 to 12 weeks.  By around September the brightly marked babies, about 12 to 15 inches long, can be found.
Keeping them at home?
        The coachwhip is not commonly kept but with some attention to their natural history, some individual snakes may do well in captivity.  They may make nervous captives and may rub their rostral scale (at the tip of the nose) raw in an attempt to escape through wire mesh.  Individual coachwhips vary in the degree to which they settle into a captive routine and eat and tolerate handling.  Those looking for a pet snake should ordinarily look elsewhere.

        Notes & References
        Within biology, distinct kinds of animals and plants are given names that help categorize them.  Within the "binomial" system, the first name or genus refers to a group of related species.  The second name or species refers to the specific kind of organism.  Generally speaking, individuals within a species can interbreed, but do not breed with individuals outside of that species.  A third name, the subspecies, is sometimes given when there are distinctly different forms within the species.  The eastern and western coachwhips are the same species, but are different enough to be separate subspecies.

Tennant, A. & R.D. Bartlett (2000) Snakes of North America: Eastern and central regions. Gulf Publishing Co., Houston.
Werler, J.E. & J.R Dixon (2000) Texas snakes: Identification, distribution, and natural history.  University of Texas Press, Austin.
Wright, A.H. & A.A. Wright (1957) Handbook of snakes of the United States and Canada.  Cornell University Press, Ithaca.

(An earlier version of this article appeared in the Cross Timbers Herpetologist in 2002.)