Last updated 23 May 2007: updated entries for B. rosaliae, B. subocularis and Bibliography.

A Look at the Family Colubridae


Trans-Peco and Baja Ratsnakes


Formerly considered members of the Elaphe genus, the Trans-Peco Rat Snakes were reclassified not long ago on the basis of certain differences, one of the most obvious being a row of five scales (suboculars) between the eye and the supralabials.

Of the two species, only B. subocularis is usually seen in the hobby. They are considered somewhat more difficult than the North American Elaphe species, requiring dryness. B. rosaliae is a protected species: please observe the law and do not smuggle or poach!

B. rosaliae, Baja California Rat Snake B. subocularis, Trans-Peco Rat Snake  

Scientific Name Common Name Distribution Size Notes
B. rosaliae Baja California Rat Snake Baja California, S California 4-4½' A rare and somewhat obscure snake that commands high prices when available. Unfortunately at least some captive populations have been illegally acquired (Grismer). In appearance it is a uniform shade of brown that may range from orange or tan to reddish (see Coloration). There are no other markings, at least in adult specimens, and the eyes have the same "bug-eyed" appearance as B. subocularis. Neither Staszko and Walls nor the Bartletts offer many suggestions about captive care, except that the Bartletts record a preference for smaller prey items (similar to B. subocularis) and the same preference of hatchlings for small lizards. Scalation details: rostral triangular; 3-6 suboculars; 10-11 supralabials; 12-15 infralabials; dorsal scales relatively small and imbricate, in 31-35 scale rows at midbody; 271-287 ventral scales; 79-94 paired subcaudals. Other: head moderately distinct from neck; pupil round; tail relatively short. Coloration: dorsally overall brownish, with specimens from some areas, esp. those with dark volcanic rock, being darker, some populations within the Cape Region of Baja California having a greenish hue, and other populations being overall straw- or mustard-coloured (Grismer); dark interstitial skin often visible; ventrum usually immaculate. Hatchlings and juveniles have a transverse pattern of thin light lines. Reproduction: little known, but juveniles have been found from June to late October, indicating a breeding season from early spring to early summer [SOURCE: Bartletts, Grismer, Staszko & Walls] B I
B. subocularis Trans-Peco Rat Snake USA (S New Mexico, Texas), Mexico (Chihuahua, Coahuila, Durango, Nuevo Leon) Max 66"/1.67m : avg 36-54"/90-137cm A fairly noticeable characteristic of this attractive snake is the large eyes, giving the Trans-Peco Rat Snake its somewhat "bug-eyed" appearance. Overall colour varies from light brown to "blonde" yellow or (occasionally and expensively) the grey phase known as the "silver morph". There are 21-28 dorsal saddles that are much darker in the normal brown coloured snakes but scarcely darker in the "blonde" phase: those on the normal coloured snakes tend to form a sort of "H" shape. These are very attractive and desireable snakes that unfortunately make delicate captives if kept in areas of high humidity, coming as they do from an arid climate. Most if not all captives will take small food items (pinkies rather than adult mice) even when fully grown, but the Bartletts note that the young may prefer small iguanids lizards such as the Uta or Anolis species. The diet of wild adults is mainly rodents, followed by bats and birds.   B I
B. s. subocularis USA (SW Texas, SE New Mexico), Mexico (Chihuahua) The nominate subspecies has 21-28 dorsal saddles.   B I
B. s. amplinotus Mexico (Durango and Nuevo Leon) This subspecies was described in 1990 and is found on the southern edge of the species' range. Since collecting is forbidden under Mexican law it is relatively unknown in herpetology. Staszko and Walls note that there are only 21-24 dorsal saddles in this subspecies  B I


A Field Guide to Reptiles and Amphibians of Eastern/Central North America, 3rd edition, expanded, Roger Conant and Joseph T Collins, Peterson Field Guides 1998.

Amphibians and Reptiles of Baja California, L Lee Grismer, University of California Press, 2002. Very extensive and well illustrated guide to the region.

Rat Snakes: A Hobbyist's Guide to Elaphe & Kin, Ray Staszko & Jerry G Walls, TFH 1994.

Corn Snakes and Other Rat Snakes (Complete Pet Owner's Manual) by R D & P Bartlett, Barrons Pet Series 1996.

Snakes: A Complete Pet Owner's Manual, by R D & P Bartlett, Barrons Pet Series.


Index of ratsnake articles (on this site).

The Bushmaster Breeding Centre in Germany specialise in breeding rat snakes, and their homepage has some outstanding photographs of various Elaphe and other species. There is also a link to the US site.

Mick Spencer has provided a very attractive table of the Elaphe, Bogertis and Sentalis species with their subspecies, common names and distribution.

A good selection of North American rat snake pictures can be found here.

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