Mex Mex Kingsnake (Lampropeltis mexicana mexicana)

Also commonly referred to as the San Luis Potosi Kingsnake, this species, in my opinion, makes some of the best pet snakes and they have so many appealing characteristics about them. Firstly, they are very docile; in all my years breeding and working with them I have yet to be bitten. Even from hatchings they are calm and docile, unlike many of the other kingsnake species that are jumpy and like to bite and musk when you try to hold them. Another thing is their size. This species is smaller than a lot of the other kingsnake species and only reaches sizes of around 60 – 90cm. Babies give little trouble when it comes to eating pinkies and all our adults are great rodent feeders. Then, to top it all off, they have amazing colouring and markings, which make them such an attractive snake!

The Mex Mex is highly variable when it comes to colouration and markings. They have an overall mottled grey to brown ground colour with saddles of black and/or red usually bordered with white. The markings on the head normally display a forked or inverted Y darker coloured marking. A nuchal blotch is common. Along their dorsal they have blotched or saddled red to brown/black markings. Their ventral markings are mottled dark and/or light grey to brown sometimes with an enlarged anterior tail blotch.

The Mex Mex occurs naturally in the Mexican States of Tamaulipas, San Luis Potosi, Coahuila, Nuevo Leon, Zacatecas and Guanajuato. Their habitat consists of dry areas of non-desert mountainous terrain.


When it comes to housing Mex Mex there are a variety of cage sizes to choose from, so a cage can be chosen according to the adult size of the snake, although smaller cages can obviously be used when the animal is growing. In fact, smaller cages for young snakes can be better in some instances because it is easier for the snake to find the food. Baby Mex Mex can be housed in an enclosure the size of a standard 11 litre Addis tub. Adult Mex Mex can be housed in something the size of an Exo-Terra desert den or a 26 litre Addis tub. The idea is to have an enclosure large enough to provide a thermal gradient.

Many hobbyists and professional breeders do not utilize glass aquariums because of their bulk and weight. If you are planning on owning more than ten or so snakes, it may be advisable to purchase a rack system or stackable reptile enclosures. A rack system looks similar to a chest of drawers: there are several rows of tubs or cages, one on top of the other, all encased in one larger cabinet-like piece. In each row there are either one, or several (depending on the size of the individual cages) plastic cages. These cages pull out from the cabinet like a drawer does from a chest. Many rack systems are “lidless”; they are built so that the cages slide back in flush with the bottom of the next row, which acts like a lid. Running along the back of the rack system is a line or two of heat cables which heats one end of the enclosure, providing a thermal gradient. Heat tape must be controlled by a thermostat in order to provide the ideal “hot spot” temperature and to avoid a fire hazard. Rack systems allow herpetoculturists to keep snakes more efficiently and to provide the correct thermal gradient.

Other options for reptile housing include manufactured cages, there are many companies specializing in custom reptile enclosures.


There are a variety of different choices to use for covering the bottom of the enclosure. Wood shavings have been a popular choice for us in a rack systems. Just be careful of cedar wood shavings or other wood shavings that have a high concentration of aromatic oils, as the oils from these products irritate the respiratory system of snakes. Sterilized reptile bark is one choice; it is attractive and easy to clean, just lift out the poop when needed, and replace all the substrate once a month. Aspen bedding can also be used; it has the benefits of bark and allows snakes to burrow, creating their own hiding spots. Less aesthetic but certainly functional choices include paper towels, newspaper, astroturf, and cut-to-fit liners.

It is important to provide snakes with hiding areas so that they feel secure in their captive environment. Hiding areas can be made out of old margarine tubs turned upside down with a hole cut in the side, cardboard shoeboxes, or my personal favourite, terracotta plant saucers with access holes knocked in the side (these come in many different sizes, are cheap, and easy to find at any greenhouse or home supply store). Many reptile product retailers also carry plastic premade hiding spots, which may be a little more expensive, but are durable and easy to clean. Several hiding spots, at least two, one on the warm side and one on the cool side, should be included in any display snake enclosure.


The most important factor for keeping reptiles is providing the correct environmental conditions. Caring for reptiles is very different than caring for other pets because reptiles are what are called ectothermic. Ectothermic, which is sometimes called “cold-blooded”, means that reptiles do not maintain a stable body temperature by creating heat from their metabolism. Reptiles rely on a behavioural mechanism called thermoregulation to regulate their body temperature. What this means is that when a reptile is too hot, it moves into the shade or down into its den to cool down, and when it needs to heat up (to digest food for example) it basks in the sun or moves into a warmer area. This is important for reptile keepers to understand because in captivity, we determine what temperatures a reptile has access to. Reptile keepers must provide a thermal gradient for their animals so that they may heat up or cool down, as they would do in the wild.

There are many different ways to provide a thermal gradient for your Mex Mex. The simplest way is buying a small heat pad, plugging it into the wall, and putting it under your animal’s enclosure, allowing it to heat up the one side of the enclosure. If you want to be extra careful you can also purchase a good digital thermometer to make sure you are providing the correct temperature range. Almost all kingsnakes do well with a maintenance temperature gradient of 28-31°C on the warm end and 21-24°C degrees at the cool end. At night, the temperature can safely drop to 18°C as long as the snake can warm up during the day. Just remember it is important to place the heating pad or cable on one end of the cage, so that the other end remains cooler. The other choice is a heat bulb. The heat bulb must be located on one end of the enclosure and most not be accessible to the snake (to prevent burns). One method that works well is to have a screen top with a clamp light sitting on top of one end of the cage. The wattage of the bulb necessary to provide the correct temperature will vary with the ambient temperature, so it is best to test the heat light by leaving it on for a few hours and monitoring the temperature closely. If the heat area provided is too hot, the snake will still use it because it must warm up to digest its food properly, but it can be seriously injured by thermal burns in the process.

Another aspect of providing the correct environmental conditions is humidity. Most kingsnakes do well with the relative humidity ranging from 40-60%. Relative humidity becomes and important issue before a snake is about to shed. Snakes shed at variable intervals, with more sheds as a snake is growing. When a snake is close to shedding its skin, its eyes will become milky and its scales will become duller. Then this will clear up and a few days after that, the snake will shed.


All snakes are carnivores; they eat only other animals. In the wild they feed on lizards and small rodents when they are available. In captivity baby Mex Mex are small but captive bred animals go onto new born pinky mice with little trouble. Generally one or two pinky mice once a week is perfect for them. As the snake grows, so should its prey. A general rule of thumb is to feed a snake a food item that is as large, or slightly larger, than the diameter of the snake at its widest point (excluding the head).

In our opinion, it is best to feed freshly killed or frozen prey that has been thawed. The reason for this recommendation is that dead mice don’t bite. If a live mouse is left in a cage with a snake that is not hungry, it can cause significant harm to the snake by chewing on it. If you must feed live, make sure to watch and make sure the snake eats; don’t drop the prey in and leave.

Overall, the Mex Mex Kingsnake is a must for anyone that is keen on Kingsnakes or Milk Snakes. With their small size, beautiful colouring and markings, and docile nature, they seem to be the ideal snakes for anyone keen on keeping snakes.



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