Keeping reptiles happy and healthy in the winter

Ben Witcomb RVN

With many if not all reptiles originating from warmer climates, it is important that we support them through the winter months. From tortoises to geckos and monitor lizards to chameleons, the husbandry of reptiles has to be correct in order for them to thrive – especially in the colder months of winter!

Let’s look at how we can continue to monitor enclosures through the winter months as well as how we can support them with colder weather.

Why do reptiles require heat?

Reptiles require heat as they cannot generate or regulate their own internal temperatures. In the wild, basking in the sun can help to raise their body temperature and they can then move into the shade once they are happy. This behaviour allows them to have control over their temperature which supports body and organ function.

Reptiles are ectothermic animals, meaning that they are cold-blooded. They solely rely on external sources of heat. Therefore, both their physiological and metabolic processes are influenced by this heat source.

When temperatures are correct in both the wild and captivity, their bodies can digest food, provide energy and support their immune systems.

What are the impacts of a colder climate for reptiles?

If a reptile’s environment is too cold, they can begin to suffer with a number of different health problems, which can lead to one unhappy little reptile.

If the environment is cooler than required, metabolism can slow down. This can lead to inappetence, lethargy and reduced digestion of food. Likewise, if the environment is too hot, they can become extremely dehydrated and cause similar symptoms.

The digestive enzymes found in reptiles can only function correctly within a specific temperature range. If they become too cold, food can stay within the digestive system and start to decompose – lovely!

Cooler temperatures can also suppress a reptile’s immune system. This can lead to infections and veterinary intervention would likely be required.

It’s important to remember that different species have different optimal temperatures – these are easily looked up.

How can we monitor temperatures and provide heat sources?

So, this all sounds very scary. It’s safe to say that we don’t want our reptiles to be unhappy and suffer with health problems due to inadequate warmth.

Let’s take a look at how we can monitor the temperatures in our enclosures, as well as how heat can be provided.

Using thermostats

Thermostats run on an automatic system that is connected to a heating element. A temperature can be set with the thermostat and a temperature probe can be placed within the enclosure. If the temperature falls below the set temperature on the thermostat, the heating element will turn on. Similarly, once the enclosure reaches the required temperature, the heating element will switch off.

We recommend placing the temperature probe around the heated area. If you are using a heat lamp, then the probe should be located where the reptile will absorb the heat. This will allow you to regulate the temperature of that specific spot.

In winter, you may notice that your thermostat is activated substantially more than during the summer months. The shift from summer to winter is a good time to assess your set-up and ensure that your heating elements and thermostat are in tip-top working order.

Basking bulbs

Many reptiles, such as chameleons and geckos do well with a basking bulb. There are a huge range of reptile basking bulbs across the market made specifically for our scaly friends. These bulbs help to replicate the natural warmth produced by the sun’s rays. They also allow the reptile to choose their preferred temperature – as there is variation in optimal temperature between individuals as well as between species!

It is important to select the correct bulb to suit the species, enclosure size and mounting distance between the bulb and the enclosure substrate.

Basking bulbs should always be used with a thermostat. Not only does this allow you to regulate the temperature, but it also helps to prevent overheating and potential burns.

UV bulbs

Some species require a UV bulb, providing them with ultraviolet light. This enables reptiles to synthesise Vitamin D, which is required for calcium absorption. Iguanas, chameleons, bearded dragons and many more reptiles require UV, so double check if your reptile requires it.

Winter is a good time to see if your UV bulb needs replacing. Check with the manufacturer instructions on how often this needs to be changed. Usually, compact UV bulbs require replacement every 6 months, but this can change depending on the brand.

An expired bulb will still light up, but will not emit the required ultraviolet rays.

A great tip to remember to replace your bulb is to coincide it with the changing of the clocks. This will eliminate the guess work! Alternatively, you can invest in a UV meter to monitor the output.

Heat mats

Heat mats work similar to a basking bulb, however they provide the heat from underneath, rather than from above. Similar to basking bulbs, these should be used with a thermostat to ensure they are reaching the correct temperature.

Heat mats should cover around one-third to one-half of the enclosure floor, allowing reptiles to move to the non-heated side if needed.

Heat mats are also species dependent and are often suited for terrestrial (floor-based reptiles) or nocturnal reptiles, as in the wild these species absorb heat stored in the environment from the sun during the day.

During the winter months, check that your heat mats are still working effectively. Sometimes, different areas of the heat mat may not activate fully, so a replacement may be required.

What is a thermal gradient?

When reptiles are provided with a heat source, the enclosure should be large enough for there to be a temperature gradient. This temperature gradient allows reptiles to move between the warmer and colder areas of the enclosure, enabling them to regulate their own body temperatures. This mimics behaviours in the wild, where they move between sun and the shade.

Both temperature zones should be monitored to ensure that they are both within optimum ranges. Especially as the cooler end might get too cold during winter!

So, how can this be achieved?

Invest in a temperature gun

What is a temperature gun? Not only do they look fancy and include a laser, but they allow owners to have a better understanding of the temperatures in their enclosures. This is especially important during winter, to ensure that the cooler end is not too cold!

Temperature guns are an accurate way to monitor temperatures and it may be useful to measure the temperatures of the enclosure throughout the day to ensure there is not a dramatic change in the evening.

What are some common temperature gradients for different species?

Temperature gradients can vary depending on the reptile species, but some common temperature gradients include:

Bearded dragon – Warm gradient: 38-42°C Cooler gradient: 24-29°C

Corn snake – Warm gradient: 29-31°C Cooler gradient: 24-26°C

Crested gecko – Warm gradient: 26-28°C Cooler gradient: 21-24°C

Veiled chameleon – Warm gradient: 32-35°C Cooler gradient: 24-27°C

Leopard gecko – Warm gradient: 31-33°C Cooler gradient: 24-27°C

Sulcata tortoise – Warm gradient: 35-38°C Cooler gradient: 24-27°C

Green iguana – Warm gradient: 35-38°C Cooler gradient: 27-29°C

Humidity levels

Many reptiles require humidity levels in order to help with hydration and shedding their skin. Reptiles that are tropical often require higher humidity in comparison to desert species.

Once winter hits and the home heating system kicks in, this can often dry out the air leading to humidity fluctuations within enclosures.

The use of a hygrometer can help you to monitor the humidity levels within your reptile’s enclosure. If you use an automatic misting system, you may need to increase the duration of the misting or the frequency to achieve higher levels.

Keeping reptiles happy this winter

As the temperatures drop outside, it’s important to make sure that our reptiles stay comfortable and happy indoors. With these creatures depending heavily on the correct husbandry, we need to take extra care during the cooler months.

By regularly checking thermostats and heating elements, we can ensure that they are preventing any problems in their enclosure and avoiding related health problems.

Small and simple actions like using a temperature gun, replacing UV bulbs and adjusting misting schedules can make a huge difference during the winter.