by Tim Spuckler
Introduction
The Mexican pine snake is of the genus Pituophis. This genus is comprised of what are commonly known as gopher snakes, pine snakes and bull snakes. The Northern Mexican pine snake is one of two large Pituophis found in Mexico; the other is Pituophis deppei deppei. Both can be distinguished from other members of their genus by the presence of only two prefrontal scales - most Pituophis have four. Mexican pine snakes, sometimes referred to as Mexican bullsnakes, are a different species from their North American relatives and scientifically are neither of the melanoleucus (pine) or sayi (bull) designation.
Description
This are easily the most colorful pine snake species. One distinct characteristic of adult Northern Mexican pine snakes is their variability - they can be a variety of different color tones. Some have solid black blotches, while others may have saddles running down their backs in 3 or 4 different colors. On many, a bright yellow background serves as the basic hue. A few individuals have coppery-orange heads. Others may have a brown background color and dark blotches, resembling Eastern fox snakes (Elaphe vulpina). In addition to an array of colors, the patterns of these snakes can also be diverse. Young Mexican pine snakes are usually dull in color. As they grow and shed, brighter colors begin to develop. They are sometimes referred to as "the ugly ducklings" of the serpent world. Pine snakes have keeled scales and relatively rough skin. Northern Mexican pine snakes can easily reach 7 feet in length and are of the typical Pituophis heavy build.
Range
These snakes live in North Central to Western Mexico, including the Sierra Madre Oriental. They can also be found in South Central Nuevo Leon and Western Tamaulipas, Mexico.
Habitat
This species frequents pine forest and high-elevation desert habitats ranging in elevation from 4500-7000 feet. Because they live at high elevations, Northern Mexican pine snakes have adapted to survive at cooler temperatures than their Pituophis relatives. Like many of its North American counterparts, this snake is infrequently seen in the field, even in areas where populations are known to exist.
CAPTIVE CARE
Housing
As with any species, a snake cage should be of adequate size, easy to clean, well ventilated, and escape-proof.
I keep an adult pair of Mexican pines in a Neodesha cage 4' x 2' x 2'. The cage has a ventilation screen on the top and sliding glass doors in the front. Northern Mexican pines don't seem to be particularly active snakes and spend quite a bit of their time hiding. They are messy, however, and the fiberglass cage structure of Neodesha enclosures is easy to clean compared to some other cage options.
Juveniles can be kept in a standard plastic shoebox for the first few months. Medium-sized individuals can be maintained in a sweater box-sized enclosure.
A hide box should be placed in the cage, as these snakes seem to be especially shy. My adults have two hide boxes, although they almost always use the same one. Plastic cat litter box trays make ideal hide areas for adult Pituophis. A filled water dish should be present at all times. Because of their preference to spending most of their time hiding and their large size, a basic, utilitarian setup seems to work best with this species. For juveniles, I use a newspaper substrate with a small rock in the enclosure. The rock effectively holds down the newspaper. By going underneath the newspaper and wedging themselves close to the rock, an effective hide area is created and utilized.
If you house them together, only do so with equal sized animals and always feed them separately. My animals never seem to show aggression towards each other and I watch them carefully for signs of stress. So far the arrangement has worked out nicely. When I feed the snakes, I put each one in a plastic sweater box with a food item. Many other snake owners keep their Pituophis together, but with caution, as problems may occur at any time regardless of previous behaviors. Housing any and all species of snake individually is recommended as a general rule.
Substrate
Pituophis are one of the more messy species of snakes in the hobby. To facilitate easy and thorough cleaning, newspaper seems to be the best bet. In addition, with cages utilizing sliding front doors, there is a tendency for cage bedding to fall out of the cage during normal cage maintenance. For setups with sweater boxes or tubs, pine shavings or aspen bedding works well. During feeding I remove my snakes from their enclosures with these types of bedding to help avoid the chance of snakes ingesting wood substrate.
Temperature
Northern Mexican pine snakes prefer relatively low temperatures. They seem to become stressed at temperatures over 80 F. 72-78 F with a drop of 5-15 F at night is ideal. For this reason I keep these snakes in the basement. During the cooler times of the year I provide a hot spot in the form of an undertank heat pad. The snakes rarely, if ever, use the hot spot; although it should be available. In the summer when ambient temperatures can approach 80, I provide no supplemental heat for my Northern Mexican pine snakes.
Feeding
Perhaps due to their adaptation to surviving at cooler than "normal" temperatures, the food intake of Mexican pine snakes compared to other Pituophis is noticabley less. Other authors have repeatedly warned against "power feeding" Mexican pine snakes, and their advice should surely be heeded. Even snakes on a moderate feeding schedule seem to have more of a proneness towards regurgitation than other types of Pituophis. Hatchlings and juveniles should be fed one reasonably sized food item every 7-10 days. I have noticed that hatchlings are much easier to get started on prekilled food items than live hopper mice or pinky rats. This may be due to the snakes' nervousness. Adults should be offered a medium sized rat every 10 days. Like other Pituophis, Northern Mexican pine snakes sometimes go through periods of time where they refuse food altogether. About 20% of the time my adult specimens will not accept food when it is offered. My breeder male refused all food from the time he went into pre-hibernation in November 2000 until breeding season ended in late May 2001. Gravid females, which accelerate their feeding, should be supplied with food twice a week, and they will usually take it both times. Due to their reduced food intake and large adult size, it typically takes 3 or 4 years to raise Northern Mexican pine snakes to adulthood.
Shedding
These snakes shed frequently as juveniles, gradually winding down to about 4 sheds a year as adults. I have never had any problems with Northern Mexican pines shedding, although I always make sure that all of the shed skin has come off - especially over the eyes and the tip of the tail. Snakes normally won't feed while in the process of shedding, so it is a good time to give them a break. They are somewhat blind while in the opaque stage of shedding and are more likely to strike. It is best to leave them alone until they complete the shedding process. After shedding, the snake's colors are at their brightest and one can often see the orange and yellow coloration developing on juveniles.
Handling
Hatchlings and juveniles are a bit nervous. They commonly vibrate their tails as a sign of their displeasure and/or raise themselves up in an "S" shape to face their source of disturbance. Most snakes exhibiting this behavior calm down once they are picked up. As they get larger, they generally become tamer. My adults are extraordinarily laid back and easily handled.
CAPTIVE BREEDING
This species is relatively easy to bred in captivity. First, make sure that the adults are at least 5 feet long to insure the least chance of problems. Adults should be brumated for a full 3 months at as close to 50 F as possible.
Since my adult pair is housed together, breeding can occur at any time, although courtship has only been observed in the spring. Fertile egg-carrying females swell considerably. Eggs are deposited in the usual manner about 6 weeks after breeding in an appropriately sized, partially covered, plastic box containing a couple inches of damp sphagnum moss. I have had eggs hatch out as early as mid-June. Northern Mexican pines have sizeable clutches of rather large eggs. An egg count of 20-30 is not unusual from an adult female. I've successfully hatched eggs at 82 F with moist perlite as the egg incubation substrate. Large and feisty neonates hatch out in about 65 days. Following the post-egg hatching shed, most hatchlings readily accept food.
Conclusion
The Northern Mexican pine snake makes a beautiful and impressive captive. If you remember keep them cooler than typical colubrids and don't overfeed them, they can give you years of enjoyment and be the highlight of your herp collection. The care and breeding of these snakes is straightforward, making them a great prospect for reptile hobbyists.
Reference
Treasure of the Sierra Madre Orientals
The Northern Mexican Pine Snake Pituophis deppei jani
by Alan Kardon
The Vivarium - Volume 7 Number 1