Turtles and tortoises are cold-blooded, which means that they cannot significantly raise or lower their body temperature independent of the environmental temperature. Their body temperature reflects the temperature of the surrounding air or water. Mammals and birds have the ability to raise or lower their temperature by increasing or decreasing their metabolism. Cold-blooded species do not have this ability, and are therefore, extremely susceptible to environmental temperatures. In fact, the regulation of external temperature may very well be the most important factor in determining the overall health of a captive turtle or tortoise.

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. 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.

Temperature

Turtles and tortoises usually have an optimal temperature range between 71 and 86°F. 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 95°F. 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 83°. Natural temperatures are rarely steady, especially for tortoises or semi aquatic 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 temperatures is very important for the health of the captive turtle or tortoise. This fluctuation in temperature is important for their health. 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 should not necessarily be provided at all times. Once again, creating a temperature and humidity environment as close to the species' natural environment is critical for long-term health.

Humidity

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, whereas, 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, pine bark mulch, peat, and moss all work to hold moisture and help keep the relative humidity high.