NESTING & EGG LAYING IN A GROUP OF AFRICAN SULCATA TORTOISES (Geochelone Sulcata)
Story By: Jason Abels – Assistant Director www.tigerhomes.org Animal Sanctuary
The Sulcata Tortoise (Geochelone Sulcata) is the 3rd largest tortoise in the world and the www.tigerhomes.org Animal Sanctuary houses a breeding colony of them. For detailed information on our group please visit Meet the Rest Of the Family.
TO SEE ANIMAL WEBCAMS
I wanted to write a brief, “Behind the Scenes,” segment on these remarkable African Tortoises for a while now. I was finally inspired to do so after observing a really cool site yesterday. I was walking around our large Sulcata Tortoise Habitat and noticed that two of our large mature female tortoises (Macy & Sahara) were laying eggs, at the same time, within a few feet of each other. I thought this was quite cool and ran inside to grab my digital camera (See attached Pictures of Egg Laying Sulcata Tortoises).
Every year our captive tortoises’ lay eggs, but it is so unusual to have two females laying their eggs at the same time like this. Egg laying in our group of Sulcata’s usually takes place from early February to late April each year, with three or four Egg Clutches separated by 30 to 35 days. For nesting material, we provide a 5 cubic yard mound of dirt for the tortoises to lay their eggs directly on the ground. Providing an “above ground” hill or mound of soft dirt to nest in makes locating nesting sites and egg recovery much easier, especially since our Sulcata Habitat is so large.
Tortoise mating behavior and nesting behavior is fascinating. Our large tortoises breed quite regularly throughout the year. The males will aggressively chase the females (very quickly) all over the habitat. When they catch up to them, they circle her, slowly forcing her to submit to mating. Without being too graphic, the male will mount the female and mate. While mating, the male tortoise will actually vocalize! You can hear the loud, grunting, mating vocalizations of the males from quite some distance. This grunting is not limited to the Sulcata Tortoise. In fact, the majority of male tortoises of other species make grunting vocalizations while breeding. After years of working with numerous varied species of tortoise, I can now recognize the species just by their breeding grunts as each species has a unique sound.
When it comes time for egg laying, the female tortoise searches for the perfect spot. Before we created the “Perfect Spot” with the dirt pile, it took our females days to find suitable nesting locations. Female Sulcata Tortoises also like to dig numerous “Test Holes” before they choose to deposit their eggs. I am never caught off guard by an egg-laying tortoise because her habitat looks like artillery shells bombed it, with holes everywhere dug over the course of many days. Sulcata Tortoises, dig their nests deep. First they dig out a large hole about two feet deep. Then they dig out a smaller “Egg Chamber” at the bottom of the larger hole. If you miss the female covering up the nesting site, it is almost impossible to locate the eggs. The female spends a lot of time making the nesting location totally indiscernible from the surrounding area.
Photo showing Macy's abandoned "Test Hole" just above her actual nesting site.
In a perfect world, I like to remove the eggs just as the female finishes laying and before she starts burying her eggs. This rarely happens and I now have a system of marking the nesting locations and the probable location of the egg chamber with rocks (See Pictures of Rock Marking System to Locate the Tortoise Nesting Area and the Egg Chamber). This saves a tremendous amount of time retrieving the eggs, especially if I do not spot the female at the perfect time. I usually have to place rocks at a distance, as well as directly on top of the Tortoise Eggs, because the female will often rearrange the rocks placed directly on top of her nest, in her efforts to camouflage the nest. For this reason, I place 2 rocks at least 6 feet away in such a way that when a line is drawn from one to the other they intersect perpendicular to each other with the intersection marking the spot.
Once the eggs are recovered, we place them in a Reptile Egg Incubator at 86-87 degrees. On average it takes 88 days at this incubation temperature for the baby tortoises to hatch. Sulcata Hatchlings are incredibly cute and are usually born with a Yolk Sac that provides them with three to five days of food after hatching.
Captive Breeding is so important on many levels. The www.tigerhomes Animal Sanctuary is proud of our productive group of breeding African Sulcata Tortoises. We hope you found this piece interesting and invite you to learn more about other species of wildlife in our “Education Center,” as well as through our World Renowned Exotic Animal Web Cams featuring the Sanctuary’s White Tigers, Golden Tigers, Black and Spotted Leopards, Mountain Lions, African Lions, as well as numerous species of rare and Endangered Lemurs , all on multiple Web Cams set up in beautiful naturalistic animal habitats.