A Biological Profile of the
Gray-banded Kingsnake
(Lampropeltis alterna)

Written by Robert W Bryson Jr.


The gray-banded kingsnake (Lampropeltis alterna) is what many people consider to be one of the most sought-after and impressive kingsnakes of North America. Their variable patterns coupled with their often strikingly coloration intrigues just about anyone, including herpetologists, who have changed the gray-banded kingsnakes systematics several times. Recently most have agreed upon its current nomenclature of Lampropeltis alterna, to which it will be referred to here on out.


Alterna are a medium-sized colubrid (a family which includes most nonvenomous snakes). They range in size from approximately 24 cm (12 in) at birth to an average adult size of 80 cm (40 in), although some wild caught specimens have reported to be larger. Alterna exhibit a large amount of variability in their patterns and coloration. It is speculated that this is due to evolutionary attempts to camoflauge the alterna to the type of rock which predominates the area from which it is found, and to mimic the Mottled Rock Rattlesnake (Crotalus lepidus lepidus) which is found in the same areas. Regardless of the reason, this variability confused early herpetologists' attempts to classify them, and until recently, alterna were separated into two subspecies, Lampropeltis alterna and Lampropeltis blairi.

Two basic color patterns exist in alterna: blairi morphs and alterna morphs. Typical blairi morphs have anywhere from 12-15 wide orange saddles often bordered by smaller black bands with usually gray saddles between them, although the orange saddles can be red to black and the gray saddles can range anywhere from a light buckskin to almost black. Most blairi morphs exhibit no alternating bands between the orange saddles, although a few might be present, especially in the more western populations. Typical alterna morphs are often categorized as having 17-23 thick black bands, occasionally split by small amounts of orange, on a gray background, and varying amounts of thinner, broken alternating bands.

These descriptions categorize typical patterns and coloration. However, not all alterna fall into these exact categories. Several have been recorded which are almost entirely melanistic. Others have been recorded that have solid thin black bands on an extremely light gray background throughout the length of the body. One specimen collected did not even have a pattern, just a solid gray body with a small amount of speckling. Geographic distribution

Alterna inhabit a relatively small region, as compared to many other snakes. Its habitat is characterized by rocky mountains and hills, where alterna reside in the extensive networks of deep cracks and fissures beneath the surface. Alterna have been found in 13 counties in Texas:

County Localities
Brewster Crane Crockett Culberson Edwards
Hudspeth Jeff Davis Kinney Pecos Presidio
Terrell Upton Val Verde

They have also been found in Eddy County in New Mexico and in the Mexican states of Coahuila, Durango, and Nuevo Leon, where they interbreed with Nuevo Leon kingsnakes (Lampropeltis mexicana thayeri) and Durango Mountain kingsnakes (Lampropeltis mexicana greeri) in the southern regions of these states where their ranges overlap. The western-most portion of their range is the Hueco Mountains in Hudspeth County, where extremely few have been reported. They extend from there to the Guadalupe Mountains on the Texas-New Mexico border, and from there south to Mexico. The eastern portion of their range was once thought to end in Val Verde and Edwards Counties, but recently alterna have also been discovered in Kinney County north of Brackettville. To the northeast of their range, alterna have recently been found in King Mountain in Upton and Crane counties. Habits

Throughout their range, alterna lead somewhat of a secretive life. They spend the majority of their time below ground in cracks and crevices where they can escape the heat of the day, and occasionally come to the surface at night, mainly in search of prey or for reproduction. Because of their secretive behavior, alterna are often thought to be rare, which led to their protection as a non-game species by the state of Texas in 1976 (they were later taken off). Surface activities usually begin to occur in early to late May in the eastern portion of their range, peak in early to late June following seasonal rain showers, and begin to decline in late July when temperatures become to hot and dry. To the west, surface activities usually accompany rain showers and peak in August to early September. Movements in both regions seem to stop as nights get noticeably cooler as fall approaches, usually in early to late October.

Eastern alterna vs. Western alterna

Discussions among alterna collectors and breeders often involve "typical" eastern locality alternas and "typical" western locality alternas . Most often this refers to the patterns and colors found on the snakes often associated with the locality from which it is from. A line of demarcation separating the two seems to run from southeastern Brewster County north. Eastern alterna most often have very few to no alternating bands and speckling on the body, and usually have a lower band count with wide saddles. Western alterna, on the other hand, usually have several alternating bands and have a higher degree of specking, usually around the head and neck region. Alterna in the east are also much more common due to more the mesic conditions, with watersheds such as the Devil's and Rio Grande rivers and Lake Amistad, whereas western alterna inhabit a more xeric region, are most often few and far between, and most are located along the Rio Grande River in southern Brewster and Presidio counties.


The diet of alterna consists primarily of lizards, such as the crevice spiny lizard (Sceloporus p. pointsetti), as well as occasional small rodents. Lizard eggs and frogs such as the canyon treefrog (Hyla arenicolor) have also been found in their stomachs. One problem alterna breeders have is getting newborn alterna to eat anything but lizards as their first couple of meals, a problem also occasionally encountered with wild caught specimens.


Reproduction in the wild usually occurs in late May and early June when suitable surface temperatures exist. Captive trials have shown that alterna most often reach reproductive maturity at three years of age, and occasionally at two. After emerging from hibernation, females usually have a voracious appetite. After a few meals, females usually shed, after which breeding usually takes place. Copulation usually lasts anywhere from three to twenty minutes. After a gestation period of about sixty days and a pre-egg laying shed, an average of six leathery, oval shaped eggs are laid, measuring approximately 36 mm in length and grow with age. Incubation time varies with temperature, but averages 62 days.


The alterna is a fascinating snake with a wide array of colors and patterns, which led to the confusion over its systematics. It is secretive, usually confined to the underground labyrinth of cracks and crevices in rocky terrain throughout its range, and was once thought to be rare. Because of its unique characteristics, it is dramatically gaining popularity, both with reptile breeders and pet owners alike, who have crowned the alterna as king of the kingsnakes.

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