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The Natural History and Captive Care of the Trans-Pecos Rat Snake – Part 1

Trans Pecos Rat SnakeNorth America is home to a great diversity of ratsnakes, many of which have long been bred in captivity.  One of the more unique species to have become established in the trade is the Trans-Pecos Ratsnake, Bogertophis (formerly Elaphe) subocularis.  Despite wide availability, its life in the wild remains largely unstudied.  Today we’ll examine what is known of its natural history, and move on to care and breeding in Part 2.


The Trans-Pecos Ratsnake ranges in color from almost pure yellow to yellowish-olive or tan, and is one of the few snakes clad mainly in this color.  It is further distinguished by dark-brown to black “H” shaped blotches between 2 long dorsal stripes and by unusually large, bulging eyes (a likely adaptation to its nocturnal lifestyle).  Light or “blond” and dark phases occur naturally, and at least 18 color varieties have been produced in captivity.  Adult Trans-Pecos Ratsnakes measure 3 to 5½ feet in length.

The Latin species’ name, subocularis, arises from the unique row of small scales located below the eyes.  This species is less-closely related to the Black Ratsnake complex (please see photo) than was formerly believed.

The Mexican race has larger blotches and had been designated as a distinct subspecies, Bogertophis subocularis amplinotus.


The Chihuahuan Desert and the Big Bend/Trans-Pecos regions of southwestern Texas (please see photo) seem to form the core of this species distribution, but it is hard to study due to its secretive ways.   It also occurs in southern New Mexico and ranges south to north-central Mexico (southern Coahuila), where it may be found at altitudes ranging from 1500-5000 feet above sea level.


Texas LandscapeThe Trans-Pecos Ratsnake inhabits deserts and desert fringes, usually in association with rock-strewn slopes and such arid-adapted plants as agave, creosote, cactus and yucca.

It spends most of its time below-ground in deep rock crevices or armadillo and rodent burrows, and is largely nocturnal.


Protected by the state of Texas due to its limited range, but field research is needed.  Some herpetologists believe that it may be more widespread than is generally believed.


Mating occurs in the spring and 2-9 eggs are laid in the summer.  The young, 12-15 inches in length, hatch after an incubation period of 2-3 ½ months.  Hatchlings feed mainly upon small lizards.


Lizards are said to be favored, especially by juveniles, but kangaroo rats, cactus mice, pocket gophers, bats (see video below) and other mammals are taken.  Prey is overcome by constriction.

Further Reading

Video: Trans-Pecos Ratsnake catching bats as they exit a cave

Chihuahuan Desert Nature Center: notes on this species’ unique habitat and other animals found there


Trans Pecos Rat Snake image referenced from wikipedia and originally posted by Cburnett

About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.
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