As ground-dwelling reptiles, tortoises in the wild simply deposit their excrement haphazardly in open areas. Liquids dry out quickly in the sun and gut bacteria are killed by the intense UV radiation. Insects, worms, and microorganisms in the soil completely decompose and utilize the droppings. Even with a high population density in an area, it is quite unlikely that tortoises will walk over the same contaminated sites several times or become overly contaminated with the droppings of conspecifics.
In captivity, however, we have a different hygiene situation due to limited space. Especially in indoor enclosures, tortoises repeatedly walk through areas contaminated with feces and urine and thus distribute feces over the entire enclosure area. In a relatively short time, an invisible carpet of intestinal bacteria and other microorganisms is formed. Substrate layers have a certain absorption capacity, but if this is saturated, harmful bacteria can also multiply unfavorably in them. In case of density stress and lack of hygiene, this bacterial load is potentiated and contaminates the tortoises again and again with their own, but also with the bacteria of conspecifics. This excessive and repeditive chain of contamination weakens the immune system of Astrochelys radiata and can lead to dangerous external and internal infections.