Everyone knows that the humidity in the jungle is higher than in the desert. But how much exactly? How much does it fluctuate from morning to evening? How can you regulate it? These questions are important and need to be clarified for each species.
Humidity in rainforest terrariums
With rainforest animals it’s no use simply building an irrigation system in your terrarium to permanently achieve 100% humidity! Our measurements during the JBL Amazon Expedition showed that during the day, the humidity dropped to 58% with increasing temperature (12:00 noon) and increased to a maximum of 92% early in the morning (2:00 - 6:00). Our measurements in Venezuela at the Orinoco showed the same trend, albeit with slightly different values: highest humidity of 96% at 6:30 in the morning and lowest humidity of 65% at 13:30 in the afternoon.
In the rainforest terrarium, water sections or a waterfall increase the humidity. The monitoring of the relative humidity and air temperature can, for example, be carried out with the JBL TerraControl .
If the humidity you achieve is not sufficient, an additional spraying with water in the evening or a sprinkler system is advisable.
Humidity in desert terrariums
As in the rainforest, the humidity decreases during the day as the air temperature increases and increases at night with decreasing air temperatures, whether in the Australian outback or in African deserts at about 20% at noon and 80% at night.
Remarkably, there are huge differences within the same region, e.g. in Tanzania/near Mount Meru: Only a few miles apart, we simultaneously found 42 °C with 16 % relative humidity and 34 °C with 44 % humidity at the same time. When aiming to keep the conditions of your terrarium animals close to nature not only the region (e.g. Arusha) but also the microhabitat (steppe, savanna, bush, height above sea level, rainforest, etc.) is important. Equally noteworthy are the differences between day and night: from a day’s maximum value of 34 °C with 44 % relative humidity, the values drop at night to 18 °C at 83 % relative humidity. These conditions should also be reproduced for a species-appropriate animal keeping.
Since the humidity is so important for a lot of animal species, e.g. when shedding skin, it also needs to be properly adjusted in the terrarium. And because many desert terrariums contain at least two climatic zones (sun area and cooling area), separate measurements are also needed from both areas. During the day the humidity values should be between 20 and 40%. At night, it might be between 50 and 70%. It is possible to adjust the moisture slightly with the help of a water bowl. The warmer the bowl, the more water evaporates and increases the humidity. In addition, some fine, light spraying may be helpful. Never aim directly at the animals when spraying!
Adding plants to your desert terrarium will increase the humidity as well. The soil introduced stores moisture and the plants also transpire and release water into the air via their stomata.