The parc extends over 6,315 hectares entirely fenced on the edge of the Sahara; a djebel culminating at 172 meters, steppes and sand dunes constitute its characteristic landscape. The vegetation is composed of various species including white sagebrush.
Sidi Toui is home to various Saharan species including mammals, such as the oryx, golden jackal, starving fox, gloved cat and fennec fox, but also different types of reptiles such as whiptail, common chameleon and snakes. Some migratory birds stop there from the Kneiss Islands.
Others, sedentary, stay there all year round. We can cite the houbara bustard, the gambra partridge, the sandgrouse, the skylark, the common raven and the isabelle course.
In the past, it used to be a place frequented by the African ostrich and the red hartebeest. The latter continued to exist between Dehiba and Hamada al-Hamra in Libya until 1912. Nowadays, both taxa are considered extinct in Tunisia. However, the red-necked ostrich is the subject of a reintroduction project in the national parks of Dghoumès and Bouhedma from individuals brought back from Morocco.
As for the hartebeest, the North African subspecies (Alcelaphus buselaphus buselaphus) completely disappeared from the surface of the Earth at the beginning of the 20th century following intensive hunting.
Proposals for the reintroduction of the closest subspecies, that of West Africa (Alcelaphus buselaphus major) have been made, but no concrete action has been taken to date.