RepVet - Photoperiod & Hibernation

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Photoperiod & Brumation

Photoperiod:

Introduction
The photoperiod is the time per day an animal is exposed to daylight or artificial light in captivity. In nature the photoperiod changes with seasons. Most animals, including herptiles, can sense these changes through an eye like organ, the pineal gland, situated in the brain. The pineal gland control certain biological processes in the body like brumation/hibernation and reproduction. For example, when the day length start to increase (i.e. from winter to spring), the pineal gland will sense this and through a cascade of hormone reactions increase the reproductive hormones, which will induce breeding behaviour.

Altitude, Latitude & Zones
The photoperiod is dependant on the geographical location i.e. latitude and altitude. The altitude is defined as the height above sea level. Higher altitudes are generally exposed to longer photoperiods and colder temperatures.

The earth can be divided into two hemispheres, namely the northern and southern hemisphere, separated by the equator. Latitude is defined as the position north or south of the equator. It is measured in degrees (°) north or south, starting from 0° to 90°. Zero degrees are situated on the equator and 90 degrees are on the poles. For convenience each hemisphere can be divided into three main zones:

Table 1 - An estimate of the three main latitude temperature zones.

Zone	Degrees (°)
1	Equator to 30
2	30 to 60
3	60 to pole

Figure 1 indicates an estimate of the latitude zones of the world.

Figure 1: Estimation of the latitude zones of the world.

The grouping of species are summarized in table 2:

Table 2 - The grouping of species according to their origin.

Area	Species	Natural Hibernators / Brumators
Around equator (0°) / tropics	Tropical	no
Zone 1	Subtropical	some
Zone 2	Temperate	yes
Desert	Desert	yes
Mountainous Areas	Montane	yes

Animals In Captivity
Some captive bred herptile species still need to be exposed to seasonal fluctuations to show breeding behaviour. Reptiles normally start to breed in spring when the photoperiod starts to increase and temperatures start to rise. Sometimes a change in temperature after winter is enough to induce breeding, but a little help from increasing the photoperiod might make things easier. To mimic the natural environment of an animal as close as possible, the changes in photoperiod also need to be taken into consideration.

When attempting to regulate the photoperiod in captivity, the geographical origin of the species must be taken into consideration (Table 2).

Temperate and desert reptiles experience seasonal fluctuations in photoperiod, as well as in temperature. These species are usually natural hibernators/brumators. Summer photoperiods in captivity should be set to fourteen hours light during the day with ten hours of darkness. During the winter the photoperiod should be ten hours of light during the day with fourteen hours of darkness.

The photoperiod and temperatures in tropical and subtropical areas are more constant at about twelve hours a day all year round. Most of these species are not natural hibernators/brumators and reproductive behaviour are regulated by night time temperatures.

Montane species live on the floors of mountain forests and are exposed to very cold winter and night temperatures. These species are usually natural hibernators/brumators.

South Africa can be divided into three photoperiod zones. The areas north of the 30° latitude line can be regarded as subtropical areas where the areas below this line such as the Cape Provinces can generally be regarded as temperate and desert areas.

Controlling The Photoperiod In Captivity
Light can be supplied in the form of natural light, i.e. the light in the room from an uncovered window or skylight, or by artificial electrical lights. Artificial light can be controlled with electric timers. The on/off interval on the cheaper timers are 15 minutes (see the Accessories & Other Stuff For Herptiles section for more info on artificial lighting and timers).

Photoperiod Tables
Photoperiod can be easily and more efficiently controlled by setting up and using a photoperiod table. A photoperiod table should contain space for the month of the year and the required photoperiod in hours for that month. The following should be considered when drawing up such a table:

Changes should not be more that one hour per month
On and off settings are dependant on aspects such as species, continental times, continental seasons and own preference

Insect eating lizards such as Bearded dragons (Pogona spp.) need to be fed daily. They are generally not fed in the two hour period before lights-on and/or in the tow hour period before lights-off. Try to keep the morning lights-on time constant at about two hours before planning on feeding (breakfast time) and only adapt the lights-off times. The same goes for lights-off and supper times.

Snakes need to be fed on a weekly basis. Night lights-off settings can be kept constant while only the lights-on times are adapted.

Also read the Accessories & Other Stuff For Herptiles section for more information on the tools and accessories you might need to manipulate photoperiods.

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Brumation:

Introduction
Brumation is the newer term used for winter dormancy (hibernation) in reptiles. It is defined as the hibernating-like state in which cold blooded or ectothermic animals spend the colder months. It is not true hibernation which is the dormant state in which hibernating animals pass the winter.

Hibernation is accompanied by reduced metabolic processes and a body temperature drop. It is more active process where the thermoregulation processes "switch off" and is marked by narcosis (reversible state of depression of the central nervous system) and a sharp reduction in body temperature and metabolism. True hibernators include some smaller mammals and birds, which poses a thermoregulation property which allows their body temperature to fall to the temperature of the surrounding air. Smaller animals have a relative large body surface to weight ratio which enables them to cool off more easily and readily. They also warm up more quickly. By reducing the body temperature and metabolic rate, the energy expenditure of the hibernating animal is greatly reduced, enabling the animal to survive longer from body energy reserves, i.e. fat.

Brumation is a remarkable evolutionary adaptation which enables temperate herptiles to survive long times of unsatisfactory temperatures and without food. It is a more passive state where the animal simply does not "warm up" and is marked by a state of lethargy and sometimes by no movement at all during the entire brumating period. Some herptiles brumate in a brumation/hibernation chamber called a hybernaculum.

Brumating Reptiles In Captivity
The main reasons for brumating captive reptiles are food shortages, large fluctuations between summer and winter environmental temperatures, physiological needs of the animal and for the induction of breeding behaviour.

Not all species needs to be brumated. Not even all species which brumates naturally should be induced to do so in captivity. Make sure the species in question can and should be brumated before attempting to do so. It is also not always necessary to brumate non-breeding captive-bred reptiles, especially when adequate food and heat is available throughout the winter months. Appropriate temperatures can be maintained by using modern heating equipment. The whole brunation process could be life threatening to the animal if the procedure is not approached correctly.

Use Figure 1 and Tables 1 and 2 above to determine the type species and brumation status of the animal.

Some reptiles, like Bearded dragons (Pogona spp.) do not actually brumate, but rather goes into a "slumber" where they stay awake, but their activity and metabolism is drastically reduced. This reduced activity is induced by colder night temperatures. During this time they have a reduced appetite with a reasonably reduced activity.

To brumate a reptile, a so called "hibernation chamber" can be prepared. This container should be small enough to ease temperature control. It is fitted with heating equipment, a thermostat to control the temperature and should contain a suitable substrate. Because animals might still be active during the brumation period, it is important to provide a water bowl with clean fresh water throughout the whole process. The water bowl should not serve as hiding as well, as it will upset the animal when supplying water. Animals should preferably be brumated separately.

The two most common mistakes keepers make is to try to brumate species which does not naturally do so in nature or to brumate a reptile that is in bad health or a bad body condition. The risk of loosing these animals becomes too big. Make sure the animal is healthy (both physically & physiologically) before continuing with the process. Generally species which come from temperate climates brumate and tropical species does not. To get animals in a state of good health and sufficient fat reserves to survive brumation, ample good quality food must be provided during the summer months.

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Brumating Snakes:

Introduction
In nature, autumn temperatures gradually decrease towards cold winter temperatures. Prey, i.e. rodents, will also start to become less abundant during this time. This temperature decrease can be done in captivity by introducing an adaptation period to the brumation process. During this period, temperatures in the container are gradually decreased to the recommended brumation temperature.

The heating equipment and thermostat in the hibernation chamber is used to regulate the drop in temperature. To ensure an adequate temperature drop potential, the chamber should be placed in a cool area (hibernation area) to create the temperature gradient. In this way the heating equipment is used to keep the chamber temperature above the temperature of the hibernation area. The thermostat are then used to gradually decrease the heat as needed during the process.

The Hibernation Chamber
Apart from the heating equipment, the thermostat and the water bowl, hiding in the form of a separate hide box (to prevent the snake from being disturbed, do not use the water bowl as hide box) and a suitable burrowing substrate should be used. The substrate layer should be deep enough for the snake to burrow in (10 - 20 cm / 4 - 8 "). Popular burrowing substrates include corn cob and dry vermiculite.

Suitable Substrates For Herptiles

Hybernation Area
This area should be equal or cooler than the brumation temperatures stated below, it should be dry and quiet to prevent disturbance. Cooling equipment can be used to obtain the required temperatures of the hibernation area.

Adaptation Period
Feeding should be stopped at about three weeks before the actual adaptation period begins. At the beginning of this period the snake should be placed in the hibernation chamber and the hibernation chamber should be in the hibernation area. During the first week the temperatures should be dropped with a third (over three weeks) of the difference between the normal summer environmental temperature and the brumation temperature.

For example, if the normal keeping temperature of the snake is 28 ºC / 82 ºF and the brumation temperature should be 13 ºC / 55 ºF, the difference of these two temperatures is (28 - 13 = 15 / 82 - 55 = 27) 15 ºC / 27 ºF. A third of this temperature is (15 ÷ 3 = 5 / 27 ÷ 3 = 9) 5 ºC / 9 ºF. The end-weekly temperatures are then calculated as follows:

Table 3 - Calculation of end-weekly temperatures.

	Normal	Week 1	Week 2	Week 3
ºC	28	23 (28 - 5)	18 (23 - 5)	13 (18 - 5)
ºF	82	73 (82 - 9)	64 (73 - 9)	55 (64 - 9)

The temperatures between the brackets indicates the calculation. From Table 3 the beginning and end temperatures are then calculated as follows:

Table 4 - Calculation of beginning & end temperatures.

	Week 1 (Start - End)	Week 2 (Start - End)	Week 3 (Start - End)
ºC	28 - 23	23 - 18	18 - 13
ºF	82 - 73	73 - 64	64 - 55

The thermostat in the hibernation chamber is then used to gradually decrease the temperatures over the period of the specific week.

Brumation Temperatures
After the adaptation period, the hibernation chamber should be kept at the recommended hibernation temperature. As a general rule temperatures between 12 - 15 ºC / 54 - 59 ºF, with the ideal of 13 ºC / 55 ºF are used. To be more accurate, brumation temperatures can be adapted according to the type of snake.

Temperate and desert snakes are usually natural brumation. These species should be brumated at 2 - 15 °C / 35 - 59 °F for a minimum of 10 weeks. Snakes from tropical areas are usually not natural brumators and only night time temperatures can be used to control breeding behaviour. Night time temperatures should not drop to below 21 °C / 70 °F. Subtropical species can be brumated at temperatures of 2 °C / 35 °F but should have access to a heat source. Montane species should be brumated at temperatures around 2 °C / 35 °F.

Species with different brumated temperatures will be mentioned in the our Care Sheet section. Other literature sources should also be consulted for specific brumation temperatures. Too high temperatures will cause the animal to deplete its energy reserves too quickly and may cause the animal to die.

Brumation Period
During this period the hibernation chamber should stay in the hibernation area. Generally brumation period should be two to three months per year, except when literature suggests otherwise. Brumation should only take place once a year.

After the recommended brumation period the temperatures in the hibernation chamber should gradually be returned to normal (reverse-adaptation). As with adaptation, this should commence with only a few degrees every day over a period of about two to three weeks (use the reverse of the principle indicated in Table 4). Once optimum temperature has been reached the animal can be moved to its original container. Food can be offered after about a week.

Problems
It is very important for a snake to have a clean empty gut before adaptation. Leftover contents can start to rot inside the animal and cause all sorts of complications that can harm or even cause death. The last meal should be at least three weeks before adaptation starts. In the week before starting to lower the temperature (i.e. the third week of no food), give the snake daily baths in warm (35 - 40 ºC / 95 - 104 ºF) water for about fifteen minutes per bath. This will speed up their metabolism and help induce defecation to get rid of the remaining waste.

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Brumating Lizards:

Brumating lizards will start to reduce their activity according to night temperatures. We keep the day temperatures and lighting constant while still feeding animals ad lib (although they will usually not eat).

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Also see our Accessories & Other Stuff for Reptiles section for more information on tools and accessories you might need to hibernate reptiles.

"If you think I should add more information to this section or think that something is incorrect, contact me and let me know. I would love to hear your ideas or methods you might use that is different than ours."

Last updated 20 May 2007 by Renier Delport

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