Choosing a Bull Snake
R.D. and Patti Bartlett
Bull snakes (also called bullsnake) are large powerful constrictors that can overcome several prey items simultaneously. They make fine pets once they are accustomed to being handled, but they can and will bite. They can hiss loudly, at times drawing attention to themselves when they would otherwise be overlooked, and some are not at all hesitant to make themselves as unpleasant as possible. Thermal burns from a malfunctioning hot rock or improperly baffled bulb or ceramic heater can be serious.
Despite all of that, bull snakes, scientifically known as Pituophis catenifer, are easy to keep for the experienced snake owner. (Thanks to their borderline belligerent attitude, they are probably not a good choice for a beginner.)
The bull snake is a denizen of plains habitats from southern Canada to northeastern Mexico. Specimens can often be seen thermoregulating themselves on the sun-warmed pavement of country roads. They also commonly enter deserted buildings, where they hunt rodents. Those preparing to shed their skin often hide in subterranean lairs or beneath ground-surface debris.
Bull snakes have lived for nearly 30 years as captives.
Adult wild (or normal) bull snakes have strongly keeled scales that may vary in ground color from tan, through straw yellow, to pale orange. A keel is a longitudinal ridge on a scale.
The head is usually the color of the ground, but dark vertical lines are present between the upper labial scales. A dark line extends diagonally rearward from the eye to the posterior throat. Prominent dark dorsal blotches run from neck to tail tip. These are rich brown to almost black toward the head, but lighten toward the tail, where on some bull snakes they can be almost red. Smaller lateral spots are present.
Because of an overhanging supraocular scale above each eye, the bull snake always looks as if it is scowling. The rostral (nosetip) scale is thickened and vertically elongate. The belly is yellow with prominent black spots.
These snake undergo very little age-related (ontogenetic) color changes. The babies may not be quite as contrastingly patterned as the adults, but are, for the most part, nearly identical in appearance.
In attitude, the bull snake varies from specimen to specimen. Some are immensely defensive, and some are placid. Some bluff by vibrating their tails rapidly while hissing in a way that sounds like pressurized steam escaping from a partially open valve – but won't bite. Others bite but are unnaturally (for a bull snake) silent.
Hatchlings are often more apt to bite than adults, and wild collected specimens are more defensive than captive-bred examples. With gentle and frequent handling, this snake usually becomes entirely tractable.
Although they can climb, bull snakes are primarily terrestrial. They are adept at following the subterranean trails of burrowing rodents, and consume many of these creatures while underground.
They are active by day in cool weather, by night in hot weather, and at dusk whenever temperatures allow. Captives seek seclusion in substrate-level hides such as curved corkbark or other commercial hideboxes.
A bowl of fresh water should be present at all times. If this is large enough for the snake to coil and fully submerge in, it may do so.
Bull snakes are large when hatched. Hatchlings may measure between 14 and 19 inches long when they emerge from the egg. If properly cared for a bull snake can attain a full 6 feet in length in the first 2 years of its life. These snakes may be active at nearly any hour of the day or night. They climb very well, but spend considerable time on the ground. The minimum floor space one or a pair should be provided with is 18 by 48 inches, the floor space provided by a 75-gallon tank.
Cage furniture in the form of sizable limbs, corkbark or other commercial hides should be provided. Be sure no furniture can shift or topple and injure your snake.
The terrarium or cage must be tightly covered with a top that will lock in place. A substrate of newspaper, packing corrugate, paper towels, dry leaves or dry mulch can be used.
Bull snakes hide much of the time, but might come out on cool days to bask under a heat-providing lamp. Be sure that the snakes cannot come in contact with a bare bulb or ceramic heating unit, lest they burn themselves. Undercage heating pads can also be used.
A cage temperature of 72 to 75 degrees Fahrenheit at night and 82 to 88 F during the day will suffice. Heat only one end of the tank to provide a thermal gradient. Winter temperatures, including that of the basking spot, can be allowed to drop a few more degrees (mid 60s night, low 80s day).
In the wild, these large snakes prey principally upon any manner of rodent that may cross their path. Both juveniles and adults may occasionally eat a lizard or a ground-nesting bird as well. Captives eat mice and rats, and hatchlings are large enough when they emerge from the egg to eat a good-sized mouse.
Usually quiet, bull snakes become active when hungry. A hatchling can eat at least one mouse a week; an adult will eat a rat or several mice every week to 10 days. Let your snake's activity patterns tell you when it's hungry.
As a rule of thumb, the largest meal you feed your snake should not greatly exceed the diameter of your snake's head. Although bull snakes can swallow comparatively large prey items, adverse temperature fluctuations or fright are more apt to cause them to regurgitate a large meal than a small one.
Although many hobbyists consider it macho to feed a snake live food, the bite of a live rodent can injure or kill your snake, and it is inhumane to traumatize the rodent. We suggest that only pre-killed prey be offered.
Even tame bull snakes may bite at feeding time when stimulated by the scent of a rodent. Approach the snakes carefully.
Baby bull snakes, wild caught bull snakes of all sizes, and those with vision impaired by an impending shed of skin, are apt to bite. Snakes typically respond defensively to fast movements, but are tolerant of slow movements.
Snakes typically shy away from movements above them, but are somewhat less wary of movements from the side. Therefore, when approaching your snake do so slowly, from the side, and only when its eyes are not clouded by an impending shed.
Do not grasp your snake by its neck. Rather, slide one hand under it about a third of the way back from the head, the other hand about a quarter of the way forward from the tail tip, and holding the snake loosely, lift it slowly. If a bull snake is handled soon after eating a large meal it may regurgitate. Do not lift the snake for a few days after it has eaten.
Wash your hands thoroughly after handling your snake or working in its terrarium to protect yourself from the possibility of contracting Salmonella, a bacteria that is often carried by reptiles and amphibians and which can cause illness in humans.
Common Diseases and Disorders
Rodent bites can be very damaging and even fatal. Never leave a live rodent unattended in your snake's cage. In fact, we suggest that you never feed a snake a live rodent.
Mouth rot (infectious stomatitis) can occur if a snake's teeth are broken, the mouth lining is injured, or if a struggling rodent being constricted, bites the snake.
Respiratory distress can occur if the cage temperature changes radically, especially if humidity is high or the cage is damp.
Blister disease can occur if the cage is too wet, and especially if the cage is both wet and dirty.
It is important that your snake shed fully. Improper shedding (retained eyecaps, etc.) may occasionally occur if your snake is not properly hydrated or if the cage humidity is too low.