Relative humidity also plays a very important role in the health of a tortoise or turtle. There are many different species of turtles and tortoises and therefore a wide variety of correct temperatures and humidity levels. This article will provide a general overview of the rough guidelines, but each individual species of turtle or tortoise should have the specific environmental needs researched and provided.
Turtles and tortoises usually have an optimal temperature range between 71-86ºF. Tortoises from arid desert regions are usually on the higher end of this range, and species from dense jungle habitats will often be toward the lower end. The critical upper limit of temperature tolerance for most turtles and tortoises is 95ºF. If they are kept at this temperature for any extended period of time, death can occur. Most turtles and tortoises will stop eating as the temperatures rise above 83ºF. Natural temperatures are rarely steady, especially for tortoises or semiaquatic turtles. In the wild there is almost always a daily cycle of temperatures with the highest temperatures in the afternoon and lowest temperatures at night. Providing these fluctuations in temperature is very important for the health of the captive turtle or tortoise. Some tortoises will prefer to lie continually under a heat lamp, which can be unhealthy, so while the optimal temperature is a good guideline, it shouldn't necessarily be provided, at all times. Once again, creating a temperature and humidity environment as close to the species' natural environment is critical for longterm health.
The second most important factor after temperature control is humidity. Humidity control can be difficult to monitor and is often overlooked, but the importance of proper humidity cannot be overstated. Improper humidity levels can lead to illness and death in all turtle and tortoise species.
Tortoise species from arid or desert-like environments are obviously going to need a low relative humidity, while those that live in a jungle setting are going to require a very high humidity. Dehumidifiers can help lower relative humidity and mist sprayers can help raise relative humidity. A wide variety of humidity controlling systems can be used, and many times the humidity can be affected by the type of substrate found in the living quarters. For tortoises requiring low humidity, sand, gravel, and rock coupled with good air circulation, may be a good option. Similarly, for species requiring high relative humidities, orchid bark, peat, and moss all work to hold moisture and help keep the relative humidity high.
Diurnal cycles are the daily cycles of light and darkness. Just as in their natural environment, captive turtles and tortoises need to have a regular diurnal cycle. For most species, 14 hours of natural or artificial light are adequate. A corresponding lowering of temperature during the night will also help replicate their natural surroundings.
The need for and length of hibernation varies widely between species. Even within a species some may hibernate, and others won't, depending on their localized climate. The hibernation requirements should be researched and followed closely for each individual species. Once you have determined the length and environmental conditions required for your species to hibernate, the following general guidelines can be followed.
The environmental temperature, humidity, day length, and hibernation — along with proper nutrition — are the most important factors in maintaining a happy and healthy captive turtle or tortoise. Each species has very different requirements, so it is essential that you adequately research your specific species. Use high quality heating, lighting, and humidity controlling devices to ensure that you provide the right environment for your tortoise or turtle.
For more information on hibernation, see our article, Box Turtle Hibernation: Pre and Post-Brumation Care, on PetEducation.com.
Highfield, A.C. Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles. Carapace Press, London; 1996.
Jenkins, J. The Veterinary Clinics of North America Exotic Animal Practice. Saunders, Philadelphia; 1999.