Several clutches are possible in the year
When breeding Radiated Tortoises, care should be taken to provide generous egg-laying areas for the females throughout the year, both indoors and outdoors. The substrate should consist of a mixture of compact garden soil and sand. This should have a depth of at least 30 cm, better 40 cm, and should always be slightly moist, especially in the lower layers. The egg-laying mound in our indoor enclosure is built over a partial floor heating and is easily accessible for the females by means of a ramp made of non-slip rubber mats. The laying mound is located under a skylight, providing a warming cone of light during the day. Additionally a Lucky Reptile Bright Sun Desert spotlight 150 Watt is installed, which can be switched on when needed. The whole laying mound is surrounded by a light privacy screen made of plants so that the females feel undisturbed and unobserved while digging. Both the indoor and outdoor laying mounds can be partitioned off so that the digging females are not disturbed by curious conspecifics. Even if no egg laying could be observed during maintenance work, it is worthwhile to check the laying mounds once a month for secretly laid eggs.
If egg-laying is imminent, the females stop feeding and begin to wander restlessly, searching and sniffing the ground. Once the female has found a suitable spot, she first scratches the surface of the ground and then begins to dig a hole with her hind legs alternately. Depending on the soil conditions, the female urinates several times to facilitate digging activities in the hard substrate. At a depth of about 10 to 15 cm, a chamber is excavated at the bottom of the pit. Once this is completed to the female's satisfaction, she pauses and begins to squeeze out her eggs at intervals of a few minutes. Using her hind legs, these are deftly placed at the bottom of the nesting pit. Depending on the size of the female, a clutch contains 2 to 6 eggs (in exceptional cases there may be more). After that, the clutch is carefully re-bedded. The entire egg-laying process can take several hours, and a lot of time is spent on covering the eggs and smudging the egg-laying traces. Since a lot of liquid is lost during incubation due to frequent urination, offering water and food after the energy-sapping egg-laying process is a matter of course.
The egg-laying season usually begins in early August and lasts until February. Thereby a clutch of eggs is laid in intervals of 4 to 6 weeks. In principle, however, clutches are possible throughout the year, so eggs are also occasionally laid from March to July. We could already observe egg-laying in the spring during the first releases in the outdoor enclosure at cool 18°C. Probably the natural and intensive sunlight has animated the females to spontaneous egg laying. Most of our females have 3 clutches per year. Some females also sometimes sat out a season, only to lay eggs again the following year. Only frequently mated females seem to lay eggs regularly. Egg size and weight can vary greatly and usually depend on the size and age of the mother.
Laying mound with privacy screen made of plants indoors | © Photo Steve Stoll
Female Radiated Tortoise laying eggs in outdoor enclosure | © Photo Alexaner Will
Young females still produce oval eggs in their first clutches, which are usually still unfertilized, whereas older and larger females always lay round eggs. There is a direct correlation between the quality of the eggs and the nutritional and health status of the mother. Poor husbandry and deficiencies have a negative effect on the composition and quantity of the egg yolk, as well as on egg size and shell thickness. If conditions are too poor, immature egg follicles are reabsorbed into the female's body and the egg maturation cycle is hormonally suspended for an extended period of time. Females from suboptimal husbandry conditions need several months, sometimes years under good conditions until the oviposition cycle can be reactivated.
FAQ on the topic of mating
For a targeted and regular breeding of Astrochelys radiata you need above all patience and perseverance. If a group of Radiated Tortoises is already raised together as young animals, the animals sometimes get used to each other under relatively low-stimulus and constant conditions, like an old married couple, in such a way that they turn out to be regular mating muffle even though they have reached sexual maturity. We therefore recommend to make the daily life of the animals more "stimulating". Raising the temperature to 30-35°C and humidity to 80%, as well as regular exposure to the sun and fresh air will work wonders. Separating the sexes for several weeks without the animals being able to see and smell each other also has a very stimulating effect when they meet again. Considering the ritualized mating behavior of the animals, the presence of several males is also beneficial. Critically check whether all husbandry parameters have been implemented consistently. If none of the measures should be effective after several repetitions, a new composition of the group with exchange of single specimens is to be considered. In rare cases an inflammation and degeneration of the ovaries caused by viruses or bacteria can occur with irreversible infertility. We consider a regular breeding program of Astrochelys radiata in an indoor environment, without access to natural sunlight, to be out of the question.