The radiated tortoise (Astrochelys radiata) is a tortoise species in the family Testudinidae. Although this species is native to and most abundant in southern Madagascar, it can also be found in the rest of this island, and has been introduced to the islands of Réunion and Mauritius.It is a very long-lived species, with recorded lifespans of up to 188 years. These tortoises are classified as critically endangered by the IUCN, mainly because of the destruction of their habitat and because of poaching. Growing to a carapace length of up to 16 in (41 cm) and weighing up to 35 lb (16 kg), the radiated tortoise is considered to be one of the world's most beautiful tortoises. This tortoise has the basic "tortoise" body shape, which consists of the high-domed carapace, a blunt head, and elephantine feet. The legs, feet, and head are yellow except for a variably sized black patch on top of the head. The carapace of the radiated tortoise is brilliantly marked with yellow lines radiating from the center of each dark plate of the shell, hence its name. This "star" pattern is more finely detailed and intricate than the normal pattern of other star-patterned tortoise species, such as Geochelone elegans of India. The radiated tortoise is also larger than G. elegans, and the scutes of the carapace are smooth, and not raised up into a bumpy, pyramidal shape as is commonly seen in the latter species. Sexual dimorphism is slight. Compared to females, male radiated tortoises usually have longer tails and the notches beneath their tails are more noticeable. Radiated tortoises occur naturally only in the extreme southern and southwestern part of the island of Madagascar. They have also been introduced to the nearby island of Reunion. They prefer dry regions of brush, thorn (Diderae) forests, and woodlands of southern Madagascar. As the radiated tortoises are herbivores, grazing constitutes 80–90% of their diets, while they also eat fruits and succulent plants. A favorite food in the wild is the Opuntia cactus. They are known to graze regularly in the same area, thus keeping the vegetation in that area closely trimmed. They seem to prefer new growth rather than mature growth because of the high-protein, low-fiber content.