Lifestyle and Lifespan
Carapace is broad, flattened and of a tan or brown color, with darker brown growth rings bordering the scutes. The anterior and posterior marginals are serrated and slightly upturned. Plastron is ivory to light tan in color, with paired forked gulars. Head and limbs are the same color as the shell and are protected with thick scales. Has one or more enlarged, conical spurs (or tubercles) on the upper hind limbs.
G. sulcata is the largest mainland tortoise in the world. They are camouflaged with their overall sandy color. Their broad, oval carapace has obvious serrations on the front and back marginals, and distinctly grooved growth rings on each scute. The front of the forelimbs are covered in prominent, overlapping scales while the hind limbs have 2-3 conical spurs that earn them their name. Males have slightly longer and thicker tails and more concave plastrons, but otherwise look similar.
Males have a gular horn jutting out of their plastron, under their head, that they can use to try to flip their competitors during mating season. Their clawed legs allow them to dig burrows to escape extreme temperatures. Thick skin and large scales on the front legs serve to protect them from their environment and other tortoises.
Hot, arid savannah, desert fringes, and acacia scrublands. Standing water only appears for short periods of time.
Mixed grasses, edible flowers, certain weeds and very small amounts of grocery store produce are recommended for captive tortoises. Any animal protein of large amounts of vegetable protein will cause carapace deformity and a shortened life span. In the wild they rely on succulent plants for food as well as most of their water.
The burrows they dig can be 10 feet deep and are significantly cooler than the air above. Other animals can use abandoned tortoise burrows for shelter from the heat.
They are crepuscular, most active at dusk and dawn. Most of their activity is concentrated in the rainy season between July and October, when succulents and annual grasses are most abundant. In the dry season they aestivate in cool burrows to conserve water. In the morning they usually bask in the sun to warm their body after the cool night.
When the weather gets too hot or cold, they will retreat to their burrows, and may stay in them for hours. During dry season they may stay in their burrows and enter aestivation. This behavior is important for them to avoid dehydration in hot weather, since they are mostly dependent on just the water in their food and metabolic water. They may also flip mud onto their backs for cooling. If temperatures exceed 100F, they will smear saliva on their front legs to further cool them down. They are able to drink up to 15 percent of their body weight when they come across water.
Even as hatchlings, these tortoises are aggressive towards each other. During mating season they become even more aggressive. Other than as hatchlings and during mating season, they are solitary.
Copulation takes place anytime from June through March, but most frequently after a rainy season in September through November. Males become very aggressive during breeding time, ramming each other repeatedly with head and limbs, and attempting to flip each other over. The female will decrease her food intake as her body swells with eggs. Nesting season is in autumn, when females look around restlessly for a good place to nest. She will kick at the dirt to make a depression, which she urinates in. It can take 5 hours of digging until the depression is about 2 feet in diameter and 3-5 inches deep. She may dig 4 or 5 nests before she chooses a suitable nest to lay eggs in. An egg is laid every 3 minutes until 15-30 eggs are laid.
15-30 eggs are laid. Once laid, the mother will leave the eggs behind. The eggs incubate for 8 months underground, until hatching. The hatchlings are 1.5-2.3 inches in length and less than 1 ounce.
Currently listed as Vulnerable by IUCN, and Appendix II in CITES
Pet sulcatas should not be released into the "wild", as they may not survive, or they may negatively impact native species.
“Sulcata” is Latin for “furrow”, referring to the deep grooves between the scutes of his carapace
Can drink up to 15 percent of its body weight at one time
They can go weeks without food or water
Will dig burrows up to 10 feet deep
They are the largest tortoise after the Galapagos and Aldabra tortoise (which they live alongside in the zoo!).
Harrold, A. 2001. "Geochelone sulcata" (online), Animal Diversity Web. Accessed September 15, 2017 at http://animaldiversity.org/accounts/Geochelone_sulcata/
Tortoise & Freshwater Turtle Specialist Group. 1996. Centrochelys sulcata. The IUCN Red List of Threatened Species 1996: e.T163423A5605057.
http://dx.doi.org/10.2305/IUCN.UK.1996.RLTS.T163423A5605057.en. Downloaded on 19 September 2017.
"African spurred tortoise" (online), Wildscreen Arkive. Accessed September 19, 2017 at http://www.arkive.org/african-spurred-tortoise/centrochelys-sulcata/image-G22487.html
"African spurred tortoise" (online), San Diego Zoo. Accessed September 19, 2017 at http://animals.sandiegozoo.org/animals/african-spurred-tortoise