San Luis Potosi x Ruthven's Kingsnake

(Lampropeltis m. mexicana x ruthveni)

Native Range:

These snakes do not exist in the wild, they are the product of captive hybridization between two closely related Kingsnakes from northern Mexico. One specie, the San Luis Potosi Kingsnake (Lampropeltis m. mexicana) is well known and highly regarded among hobbyists for it's large size, attractive red-orange squarish blotches on a gray background and gentle disposition. The other specie, the Ruthven's Kingsnake (Lampropeltis ruthveni), is poorly understood by taxonomists. It resembles a typical Milksnake in appearance and its' babies are well-known for being small and somewhat problematic feeders. However, it is available in an amelanistic albino form.

Since hybridization between these two forms was already known, we decided to cross amelanistic specimens of Ruthven's Kings to some very attractive San Luis Potosi Kings in our collection. It was hoped to produce albinos specimens combining the positive features of both snake, while removing the negative features. The plan worked, and today lovely albino and heterozygous specimens of these snakes are available.


6-7" at hatching, adult may exceed three feet, but most are smaller.


These snakes will rarely attempt to bite, although they may do so if restrained. Handle gently, without pinching or squeezing, allowing the snake to move through your fingers. Do not allow the snake to dangle unsupported.


Any ‘typical’ snake cage can be used, with a fifteen-gallon aquarium being adequate for an adult. Hatchlings are sensitive to dehydration and do best in small ‘Critter Keeper’ cages or plastic shoe boxes. Due their secretive nature, be sure to provide adequate hiding areas. Rock cracks and crevices are preferred over larger, more spacious hide houses. Many keepers use small shallow pottery (plant pot drainage saucers) successfully.


A variety of substrates can be used. Aspen bedding, newspaper, and Care Fresh are popular with many keepers. Paper towels may be used for lining baby cages. Keep the substrate clean and dry at all times. As with all reptiles, do NOT use cedar or pine shavings. These items are toxic to reptiles.


Most California Kingsnakes will be fed a diet of mice throughout their lives. Hatchlings usually feed readily on newborn ‘pinkie’ mice, and should be fed about every five to seven days. Increase the size of the meal as the snake grows. One or two adult mice are sufficient every ten or fourteen days to maintain even the largest adult. Often, hatchlings feel ‘lost’ or insecure when placed in a large cage. These animals will often feed readily if left overnight in a small deli cup with a pinkie and a folded paper towel to hide under.

Humidity & Water:

Provide clean water in a small dish. Humidity should be kept low, or respiratory problems can result. Due to the variance in cages and home environments, some snakes may experience shedding problems, particularly the tail tip. If this is noticed, provide a small plastic container with lid (cut an access hole in the side) filled with damp sphagnum moss. This will allow the animal to shed properly. Stuck sheds may harden and constrict the blood flow to the tail, causing loss of the tail tip. Many shedding problems can be rectified if noticed quickly simply by placing the snake in a small deli cup overnight with a wet paper towel. Place the cup in a suitable location in the cage.

Heating & Lighting:

Provide a thermal gradient by placing a heat pad under one end of the cage. This should allow the snake to choose from higher temperatures (about 80F) at the warm end, and cooler temperatures (about 70F) at the cooler end. Provide suitable hiding areas at both warm and cool areas, so the snake can feel secure at any temperature. Temperatures below 65F should be avoided. No special lighting is required for these animals. Many specimens will refuse food during the winter months, an indication that they wish to hibernate. These specimens may be kept at 50-55F for two to three months and will resume feeding when returned to warmer temperatures.


Although examining the shape of the tail can sometimes determine sex, many adult snakes can only be accurately sexed by ‘probing’. Hatchlings can be sexed by manually everting the hemipenes (a process known as ‘popping’). Probing or popping should only be performed by an experienced individual, as improper technique may result in severe damage or even death. A brumation (hibernation) period of about three months at 50-55F is generally required to induce breeding. Typical clutches consist of three to five eggs. Incubation takes from 55 to 60 days, at an average temperature of 80F.

Color and Pattern Phases:

Widely variable, likely due to the crosses involved in creating these snakes. Snakes ranging from near duplicates of the square-blotched San Luis Potosi ancestors to milksnake phase animals resembling the ancestral Ruthven's Kingsnakes may be present in a single clutch.

© 2001 VMS Professional Herpetoculture (