African spurred tortoise
|African spurred tortoise|
|At Oakland Zoo|
The African spurred tortoise (Geochelone sulcata), also called the African spur thigh tortoise or the sulcata tortoise, is a species of tortoise which inhabits the southern edge of the Sahara desert, in northern Africa. It is the third largest species of tortoise in the world and the largest species of mainland tortoise (not found on an island).
Taxonomy and etymology 
Its generic name is a combination of two Greek words: geo (γαῖα) meaning "earth" or "land" and chelone (χελώνη) meaning " tortoise". Its specific name sulcata is from the Latin word sulcus meaning "furrow" and refers to the furrows on the tortoise's scales.
Range and habitat 
The African spurred tortoise is native to the Sahara Desert and the Sahel, a transitional ecoregion of semi-arid grasslands, savannas, and thorn shrublands found in the countries of Burkina Faso, Chad, Eritrea, Ethiopia, Mali, Mauritania, Nigeria, Senegal and Sudan In these arid regions the tortoise excavates burrows in the ground to get to areas with higher moisture levels spending the hottest part of the day in these burrows. This is known as aestivating. Burrows may average 30 inches in depth; some dig tunnel systems extending 10 feet or more underground.
Size and lifespan 
The Sulcata is the third largest species of tortoise in the world after the Galapagos tortoise, and Aldabra Giant Tortoise; and the largest of the mainland tortoises. Adults are usually 24 to 36 inch long (60–90 cm) and can weigh 100-200 pounds (45 – 91 kg). They grow from hatchling size (2-3 inches) very quickly, reaching 6-10 inches (15–25 cm) within the first few years of their lives. The lifespan of an African Spurred Tortoise is about 50-150 years, though they can live much longer. (The oldest in captivity is 54 years, located in the Giza Zoological Gardens, Egypt, 1986).
Sulcata tortoises are herbivores. Primarily, their diet consists of many types of grasses and plants. Their diet is high in fiber and very low in protein. The consumption of too much protein can cause their shells to take on a pyramid appearance. Feeding of fruit should be avoided.
As pets 
Due to their reputation for having a pleasant temperament, more and more sulcata tortoises are brought home as pets. However, these animals provide significant challenges to their keepers, due to their dietary, temperature requirements, and their size.
A captive diet for G. sulcata should be organized around five important factors: high dietary fiber, low protein, low fruit or sugary foods, adequate calcium, and not overfeeding. Grasses should make up at least 75% of a captive sulcata's diet, to provide the high dietary fiber found in the wild. Young sulcatas grow very fast - they can easily double in size each year during the first three years. For proper bone and shell development, their diet must include adequate calcium. In the wild, this is provided by a high calcium content in the soil, and therefore in their diet, but in captivity calcium supplements are required.
Many "wet" vegetables can cause health problems in large quantities. Red leaf lettuce, prickly pear cactus pads, hibiscus leaves, hay from various grasses and dandelions are some of the better foods to make up the bulk of their diet. They will attempt to eat most types of plants eventually and some common garden plants can be very toxic to them, such as azaleas.
Protein is lacking in their natural diet, and should not be fed in captivity. Lack of calcium combined with high protein does contribute to some shell malformations and causes pyramiding. Fruit should only be given in moderation. They will eat protein such as caterpillars and snails if given the opportunity, but this should be a very small portion of their diet.
The diet available to captive sulcatas can be much more nutritious than in the wild, which offers its own challenges. Sulcatas are voracious to offset the dearth of nutrients in their natural habitat; care must be taken to insure the tortoise does not overfeed. Bedding, or other plant material in their enclosures, should be restricted to grasses or grass-based hay, to ensure that the animal does not take in too much nutrition.
Sulcatas should be kept above 60F(16°C), which means many areas will require special winter accommodations. Sulcatas need a large enclosure as they get bigger and should be given a generous grazing area. Their high fiber diets (grass), their temperature requirements, and their space requirements, mean they are challenging pets.
Per CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora), a zero annual export quota has been established for Geochelone sulcata for specimens removed from the wild and traded for primarily commercial purposes.
Copulation takes place right after the rainy season, during the months from September through November. Males combat each other for breeding rights with the females and are vocal during copulation.
Sixty days after mating, the female begins to roam looking for suitable nesting sites. For five to fifteen days, four or five nests may be excavated before she selects the perfect location in which the eggs will be laid.
Loose dirt is kicked out of the depression, and the female may frequently urinate into the depression. Once it reaches approximately 2 feet (60 cm) in diameter and approximately 3-6 inches (7–14 cm) deep, a further depression, measuring some eight inches (20 cm) across and in depth, will be dug out towards the back of the original depression. The work of digging the nest may take up to five hours; the speed with which it is dug seems to be dependent upon the relative hardness of the ground. It usually takes place when the ambient air temperature is at least 78 F (27 C). Once the nest is dug, the female begins to lay an egg every three minutes. Clutches may contain 15-30 or more eggs. After the eggs are laid, the female fills in the nest, taking an hour or more to fully cover them all.Incubation should be 86 to 88 degrees F, and will take from 90 to 120 days.
- Fritz Uwe; Peter Havaš (2007). "Checklist of Chelonians of the World". Vertebrate Zoology 57 (2): 279–280. ISSN 18640-5755. Archived from the original on 2010-12-17. Retrieved 29 May 2012.
- Tortoise & Freshwater Turtle Specialist Group (1996). "Centrochelys sulcata". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 2 February 2011.
- Kaplan, Melissa. (1996)African Spurred Tortoises. Reptile and Amphibian Magazine, September/October 1996, pp. 32-45
- Branch, Bill (2008). Tortoises, Terrapins & Turtles of Africa. South Africa: Struik Publishers. p. 128. ISBN 1-77007-463-5.
|Wikimedia Commons has media related to: African Spurred Tortoise|
- ARKive - images and movies of the African spurred tortoise (Geochelone sulcata)
- Sulcata Tortoise - also known as African Spurred Tortoise. Care Sheet and Pictures