Humidity

BRB Humidity

Maintaining the correct levels of humidity is a crucial aspect of maintaining Brazilian Rainbow Boas. Creating a humid environment is a fairly easy process but many beginners struggle due to inadequate research or poor husbandry advice. Here is my guide to creating and maintaining humidity. 

Heating

Humidity is the measure of water vapour in the air, and warmer air holds more moisture than cooler air. Therefore it is important that the enclosure is kept at the correct temperature.

Rainbow boas are not as tolerant of high temperatures as most other boas, serious neurological problems can occur if they are kept at temps of 32°c (90°f) for long periods. The temperature should range from 21°c (70°f) at the cool end, rising to no more than 30°c (86°f) at the warm end. The ideal basking temp should be around 28°c (84°f).

Misting

Misting the enclosure is the one of the best ways to increase the humidity and should be part of a 24hr cycle. The enclosure can be misted at least once per day, but not excessively. Simply drenching the enclosure on a regular basis will not increase the humidity; being constantly damp and warm will only serve in creating the perfect environment for bacteria and mould to grow.

Invest in a good quality pressure sprayer

Shortly after misting the enclosure, a build up of condensation will appear on the sliding glass doors; a good indication that the correct level of humidity has been reached. The condensation should remain for several hours or so and then begin to gradually decrease as the enclosure dries out. If you are finding that the enclosure is drying out to quickly then you may need to adjust the amount you are misting. Such fine tuning should ideally be carried out before you acquire the snake.

Here you can see the build up of condensation on the glass doors shortly after misting the vivarium

I usually only mist my BRB’s enclosure once day, but in the week prior to them shedding their skin I increase this to twice a day, to ensure good results.

In my opinion pressure sprayers are much better than electronic fogging machines for two reasons. For one a decent fogging machine can cost upwards of £50, plus the cost of running and maintaining it. You can buy a pressure sprayer for as little as £8. Secondly a pressure sprayer offers a more hands on experience and encourage keeper's to be more vigilant.

Humid Hide

I always recommend the use of a ‘humid hide’ filled with damp Spaghnum moss to be included within the enclosure. The humid hide will guarantee that your BRB will always have access to an area with near 100% humidity levels, no matter what time of the day.

You can buy ready made ‘humid hides’ made from resin which resemble a log or tree stump, but a decent sized one is not cheap.

A much more cost effective method of making a moss tub is to use a plastic container like a sandwich box. A plastic container may not be as aesthetically pleasing, but they do the job just as well as anything ‘shop brought’ and I’ve personally used them for years. Using a small craft drill you will need to cut open an entrance and drill some air holes evenly around the each side of the tub. It is very important to increase the size of the entrance as the snake grows, and to accommodate its increased girth after feeding.


Here is an example of one of my humid hides made from a plastic container
 

 Once the tub has been modified it can be filled with damp sphagnum moss and placed in the warm end of the vivarium. The moss can be sprayed with warm water every few days, to keep it moist (not drenched) and ensure the humidity levels stay high.

A humid hide being used by my male BRB whilst in shed

Substrate

Creating a humid environment also requires the correct substrate. Orchid bark, Cyprus mulch and eco-earth are all popular choices with many rainbow keepers and very good at holding moisture. The orchid bark can be mixed with damp sphagnum moss.

Extra care should be taken if you are housing your BRB in a wooden (melamine-coated chipboard) vivarium. Melamine does not react well to being in constant contact with damp substrate and will soon begin to warp and crack. Cyprus mulch and eco-earth should be avoided in this instance.

Helpful hint; Before adding fresh orchid bark to my BRB’s vivarium I always give it a quick 1 minute blast in the microwave. I do this for two reasons. Firstly orchid bark can harbour mites and their eggs. Secondly heat and humidity is lost whilst the enclosure is open and warm bark helps not only to reheat the vivarium but boost the humidity levels.

Place the bark in a microwavable dish and spray lightly with warm water before microwaving it

Ventilation

The ventilation in the enclosure should never be sacrificed in order to make it humid. Simply covering up all of the ventilation will cause the air to become stale and will interrupt the humidity cycle.



A plexi-glass covering screen

That being said, excessive ventilation such as the mesh screens found on glass and plastic vivarium's will need to be modified, as these enable too much heat and humidity to leak out of the enclosure. The best solution for this problem is to make a plexi-glass (plastic) screen for the mesh. Plexi-glass can be cut to any shape or size using a Stanley knife and a mini craft drill. You can even improve the appearance of the plexi-glass by covering it with a wood effect sticky back plastic.
 

A Plexi-glass screen complete with wood effect covering

Snake Senses- Thermal Imaging

 

Snake senses- Thermal Imaging

 

Snakes are primarily nocturnal hunters. To assist them during low light conditions; the pythons the boas and the pit vipers have developed highly sophisticated thermo-sensory facial pits (heat receptors), which allows them to strike at their prey with incredible accuracy even in complete darkness.

Anatomy

Although they serve the same purpose, the anatomy of the heat pits found on the pythons and boas is different to that of the vipers.

On a viper there is a single external pit is located between the eye and nostril. Each has a thin sensory membrane suspended above an air filled pocket which acts as an insulator for the detector. This highly vascular membrane contains some 1600 sensory nerve endings, which sprout from around the trigeminal nerve. The membrane has a narrow tube linking the inner and outer pockets which can be opened and closed by the surrounding muscle. Being able to open and close the tube helps to maintain an equal amount of pressure either side of the membrane. Too much or uneven amounts of pressure would impair the heat peats.

This Copperhead viper has a single pit either side of its head, situated between the eye and nostril

In contrast the pythons and boas have a series of pits in and around the labial (lip) scales on either side of the head. The pits vary in size and number depending on the species; some are very shallow and almost unrecognisable, whereas others are deep and highly obvious. Although both types of snake posses heat pits, they both differ in how they are positioned. The heat pits from a Python are set into the labial scale itself; the Boas are set in between the scales. Each pit is lined with a membrane rather than a single suspended one, and although packed with nerve endings, their density is quite a bit lower than those found on the vipers. The lower density is probably attributed to the fact that there are multiple heat sensors as apposed to a single organ.


Here are the visible heat pits found on the Brazilian Rainbow Boa



 



The heat pits are not visible on a Boa Constrictor



It is fascinating how these two groups of snakes have evolved such a similar sensory ability, especially considering that pythons and boas are considered to be ‘primitive’ snakes in comparison to the more advanced pit vipers.

How do they work?

 The sensory membrane fires nerve impulses at a constant slow (neutral) rate. The neutral range is determined by the average temperature of all heat radiating objects within the heat pits range. When a particular heat source is within this neutral range it does not bring about any changes in the rate of firing. When a heat source exceeds a certain temperature, i.e. being above the neutral range, the nerve impulses begin to fire at an increased rate. The nerve endings are incredibly sensitive and can detect a change in temperature of less than 0.002°c. They can even differentiate the heat radiated from an animal and that from a rock warmed by the sun, a very useful function, which prevents the snake from striking out needlessly at anything giving off a heat signature.

The nerve impulses are sent to a region of the brain called the optic tectrum. The optic tectrum can process both thermal and visual information. Some of the neutrons (nerve cells) within the optic tectrum respond only to infrared signals, others to visual input and some to both inputs simultaneously. Here the two sets of information are sorted and combined to create a 3D thermal image.  Because of their position on either side of the head, the pits can work in stereo enabling the snake to better judge the range and bearing of its prey. A snake armed with heat receptors can strike at its prey with pinpoint accuracy. The neck and chest areas generate the most heat and are targeted most commonly.

Sensory overload

When in use the pits absorb a lot of thermal information. To cope with this thermal overload they have developed ways to remain functional. The pits inevitably become hot and need to be cooled. They do this receiving oxygen which in turn cools the membrane and returns it to a thermo-neutral state. Constantly absorbing new information means that the pits need to reset regularly. When a warm object is placed in front of the pit, its nerve firing rate will increase until it reaches its peak and levels off. At this point the pit has effectively become accustomed to the heat source. When the heat source is removed the firing rate decreases and reverts back to its thermo neutral state; a process which takes just over 50 milliseconds.

 

 

Welcome

Welcome to the reptile blog.
As you may already know, I have a real passion for animals, in particular reptiles. I've successfully kept reptiles for over eight years, and am well experienced in their husbandry and care. The condition of my snakes speaks for itself and is something I am very proud of.
I regularly attend reptile handling days and nothing gives me greater pleasure than changing peoples perceptions of reptiles and offering advice to reptile hobbyists.
So I hope enjoy the blog and feel free to ask questions, ill do my best to answer them.