Thermo-Regulation and Thermal Gradients - A Guide To Setting Up a Vivarium

Nearly every care sheet I've ever read states something along the lines of "Royal Pythons should be kept at a thermal gradient of 26 to 33 degrees Celsius", but rarely go into detail about how to provide this gradient, or why it is necessary - as a complete novice, just the statement its self can spark confusion. In-depth information can be found for both these questions by scouring the internet, but I specifically remember my own frustration at the mass of conflicting information regarding methods, so I'll attempt to cover this with a description of how I personally do things here. But before we get into the hows, I'll cover off the whys...

Thermo-regulation:

Snakes, like (almost) all reptiles, are cold blooded - which means they are unable to produce their own body heat, and solely rely on their local environment in order to control their temperature. They require a certain amount of heat in order to function, notably to be able to digest food. When they are too cold, they seek out heat in a manner of ways, or by "exothermic means" - some will bask in direct sunlight, some will lay on rocks that have heated up in the sun, or search out warm spots in the nooks and crannies of the landscape. When they are too warm, they must move to cooler, shaded areas to lose heat and cool down. They will often do this multiple times per day, depending on the temperatures. In captivity, there is much we can do to simulate their natural environment and behavioural patterns. Having a both warm and cooler areas of the vivarium - or a thermal gradient - is vital for captive snakes to thermoregulate.

Thermal Gradients (How-To):
After getting to grips with a basic understanding of thermoregulation and how snakes use their environment to control their temperatures, my challenge was finding a way to best provide my own snakes with the ability to thermoregulate correctly within the confines of a vivarium to promote a natural behaviour pattern. This took a few attempts of trial and error to perfect, especially in terms of bulb wattage, bulb placement, and crucially, thermostat probe placement - I cannot put enough emphasis on just how crucial a thermostat is to achieving correct temperatures and a thermal gradient within a vivarium, as well as safely controlling the maximum output of the heat source to protect your snake.

About here.

My chosen and preferred method of heating my vivariums is with ceramic bulbs controlled with pulse proportional thermostats. Infra-red bulbs come in at a close second, but I'm not a fan of the constant red glow. Heat mats inside vivariums do next-to-nothing for ambient (air) temperatures, and in my opinion do not belong in vivariums, so I'm not even going to touch on these. A 100watt ceramic bulb should be ample to heat a 3 foot vivarium. The best place I have found to mount these bulbs is on the ceiling of the vivarium, positioned at roughly one-quarter of the length of the roof, and half way between the front and the back. This should give a good hot spot temperature, as well as allowing enough room away from the bulb for the cool end to be a few degrees lower than than the warm end. Once you have secured your ceramic bulb and holder, you absolutely MUST install a heat lamp cage around the bulb - I cannot stress this enough, ceramic bulbs get incredibly hot. If a snake comes into contact with an unguarded bulb (and trust me, it will), it will cause truly horrific injuries to the snake. Please use one.

Next up: Thermostat probe placement. This was an area in particular where every man and his dog seemed to have an opinion on - I must have tried them all, and got mixed or poor results. I like to have mine secured to the middle of the side wall at the hot end, at about 2 inches higher than the substrate level. I use those little white plastic cable clips that you use for clipping wires to the skirting board to hold the probe wire firmly in place. With the probe positioned here this way, it cannot be moved around, and the snake cannot lay on top of the probe blocking it from monitoring the current temperature and affecting the output of the bulb. This is also a good place to attach the thermometer probe to monitor the hot end ambient temps - one should also be placed at the cold end. My crudely drawn diagram shows this much better than I can word it - pay particular attention to the positioning of the thermostat probe one the left hand side.

Now it's time to turn everything on, and let the bulb get up to temperature. Once the bulb has warmed up, place the thermometer probe directly underneath the bulb, and adjust the thermostat slowly until the thermometer reads 33 degree Celsius, and comfortably stays there. With the hotspot remaining stable at 33C, the temperature from the side wall to around half way along should read 30 degrees C, gradually reducing to mid 20's at the furthest point from the bulb.

So long as the hot spot is static at 33 degrees, the immediate area around this should be around 30C. I do not concern myself too much with the cold end temperatures so long as the fall below 26 degrees. Whilst this may fall below the generally advised temperature, it is important to have an understanding of thermoregulation and how snakes react to their environment - which is why I tackled the subject first. With a cold end temperature of below 26 degrees, the snake will spend relatively short periods of time in this zone, returning to the warm end for extended periods of time to absorb heat, and moving back to the cool end again to lose heat. This is exactly how a cold blooded reptile should behave and naturally would behave - and so long as they have a sufficient heat source, as well an area to cool down, they will fully utilise the provided thermal gradient available to them. Problems are not caused by having an area "too cold", they are caused by too high temperatures in the cold end, restricting the snakes ability to cool down.

As a final note, it is worth mentioning that timid Royal Pythons in particular will chose a "favourite" spot where they feel most secure, and will opt to remain in this spot regardless of their temperature. Hides must be available within both the hot and cool zones of the vivarium, and having some sort of coverage in between the two will help the snake feel secure when moving between the areas to thermoregulate - and a secure snake is a happy snake, which should in turn reduce the eventuality of problematic feeding issues. A topic I'll tackle another day.