African Spurred Tortoise

Characteristics

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.

Species Specifics

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.

Physical Characteristics

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.

Ecology

Habitat

Hot, arid savannah, desert fringes, and acacia scrublands. Standing water only appears for short periods of time.

Distribution

Diet

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.

Ecological Web

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.

Activity and Behavior

Activity Pattern

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.

Behavior

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.

Social Behavior

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.

Reproductive Behavior

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.

Offspring

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.

Conservation

Status

Currently listed as Vulnerable by IUCN, and Appendix II in CITES

Historical

Current Threats

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