The Trans-Pecos rat snake or Davis Mountain rat snake (''Bogertophis subocularis''), is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of medium to large, nonvenomous

rat snake Rat snakes are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemi ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Colubridae. ''Bogertophis subocularis'' is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the

Chihuahuan Desert The Chihuahuan Desert ( es, Desierto de Chihuahua, ) is a desert ecoregion designation covering parts of northern Mexico and the southwestern United States. It occupies much of far West Texas, the middle to lower Rio Grande Valley and the lo ...

Geographic range

The Trans-Pecos rat snake is found in the Mexican states of Chihuahua, Coahuila, Durango, and Nuevo León, and its range extends northward into

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

and

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ke ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

. Wright, Albert Hazen; Wright, Anna Allen (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock. 1,105 pp. (in two volumes). (''Elaphe subocularis'', pp. 255-259, Figure 79 + Map 23 on p. 223).

Description

''B. subocularis'' has a row of small scales ( suboculars) between the lower border of the eye and the

upper labials In reptiles, the supralabial scales, also called upper-labials, are those scales that border the mouth opening along the upper jaw. They do not include the median scaleWright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates ...

. Schmidt KP, Davis DD (1941). ''Field Book of Snakes of the United States and Canada''. New York: G.P. Putnam's Sons. 365 pp. (''Elaphe subocularis'', pp. 152-153, Figure 41). Coloration is yellow to tan

dorsally Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

with a series of black, or dark brown, H-shaped markings. Conant R (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. Boston: Houghton Mifflin. xviii + 429 pp. + Plates 1-48. (hardcover), (paperback). (''Elaphe subocularis'', p. 197 + Plate 32 + Map 151). The eye is large and prominent, light-colored with a contrasting round black pupil. The tongue is pink. The

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down t ...

are in 31-35 rows at midbody. The

ventrals In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that cont ...

number 260-277; the

subcaudals In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...

number 69-79. Smith, Hobart M.; Brodie, Edmund D. Jr (1982). ''Reptiles of North America: A Guide to Field Identification''. New York: Golden Press. 240 pp. (hardcover), (paperback). (''Elaphe subocularis'', pp. 184-185). Adults are usually 36-54 inches (90–137 cm) in total length (including tail). The record total length is 66 inches (168 cm). Powell, Robert; Conant, Roger; Collins, Joseph T. (2016). ''Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition''. Boston and New York: Houghton Mifflin Harcourt. xsiv + 494 pp. . (''Bogertophis subocularis'', p. 384 + Plate 35).

Habitat

The Trans-Pecos rat snake's

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

consists of desert flats and brushy slopes, and rocky outcrops where it dens.

Diet

''B. subocularis'' feeds on small

vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with c ...

Behavior

A nocturnal species, ''B. subocularis'' is uncommon and rarely seen in the wild, save on warm summer nights during the breeding season. Nicknamed "suboc" by enthusiasts, it is nonaggressive when approached, even passive, and is easily raised in captivity.

Sexual dimorphism

''B. subocularis'' exhibits

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

. Females are larger than males as adults. Adult males reach between 3.5 and 4.5 feet (1.1-1.4 m) in total length (including tail); whereas females grow up to 5.5 feet (1.7 m).

Reproduction

The breeding season for ''B. subocularis'' runs through May and June, while

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

-laying begins in July and ends by September. At nearly three months, their incubation period is lengthy for a snake, at the end of which a clutch of anywhere from three to 11 snakes, each in total length, hatch. As they are hatched during winter, the hatchlings may remain hidden underground for several months before venturing outside.

References

External links

Simply SubocsSuboc.com
{{Taxonbar, from=Q2697414 Colubrids Fauna of the Chihuahuan Desert Reptiles of Mexico Reptiles of the United States Reptiles described in 1901