The radiated tortoise (Geochelone radiata) is found in the southwest corner of Madagascar. This endemic species is confined to an area known as the spiny forest. The Madagascar spider tortoise (Pyxis arachnoides) is also found within the same habitat. The majority of the plants found are dominated by two families, the Didieraceae and Euphorbiaceae. The leaves of these plants, native grasses and the introduced Opuntia cactus make up the majority of this tortoises diet. Consuming droppings from bush pigs and zebu cattle have also been reported.
The radiated tortoise is an endangered species and listed as CITES I. Over the last twenty years the estimated population has fallen from 20 million animals to only 4.5 million. The primary threats to the survival of these tortoises are conversion of land to agriculture, as well as illegal trafficking for food and the pet trade. Until recent times, these tortoises were protected from the illegal trade because of the native's belief that it was taboo or fatal to even touch one. As various cultures have blended in Madagascar, the taboo has fallen to the way side as a need for food and money has taken precedent.
In captivity, the radiated tortoise has been one of the most successful Species Survival Plan breeding programs. Two institutions in particular are to be thanked for this success, the Wildlife Conservation Society's, St. Catherine's Island breeding program, and the Gladys Porter Zoo. The Knoxville Zoological Gardens is currently maintaining animals only for exhibit. During the late spring through early fall, our two males can be seen on exhibit in Tortoise Territory.