The African spurred tortoise (Centrochelys sulcata), also called the sulcata tortoise, is a species of tortoise inhabiting the southern edge of the Sahara desert in Africa. It is the largest mainland species of tortoise in the world, and the third-largest in the world. It is the last remaining species in its genus, Centrochelys, with the five other species in the family already extinct. The African spurred tortoise is native to the Sahara Desert and the Sahel, a transitional ecoregion of semiarid grasslands, savannas, and thorn shrublands found in the countries of Burkina Faso, the Central African Republic, Chad, Eritrea, Ethiopia, Mali, Mauritania, Nigeria, Senegal, Saudi Arabia, Sudan, Yemen and possibly in Somalia, Algeria, Benin, and Cameroon. It is possibly extirpated from Djibouti and Togo. They are found on hills, stable dunes, and flat areas with shrubs and high grass. They also like to settle in areas with interrupted streams or rivers. In these arid regions, the tortoise excavates burrows in the ground to get to areas with higher moisture levels, and spends the hottest part of the day in these burrows. This is known as aestivation. In the wild, they may burrow very deep; up to 15 m deep and 30 m long. Plants such as grasses and succulents grow around their burrows if kept moist and in nature they continue to grow for the tortoise to eat if the soil is replenished with its feces. Sulcata tortoises found in the Sudanese part of their range may reach significantly greater size at maturity than those found in other regions. (Source: Wikipedia.org, CC BY-SA)