Radiated Tortoise (Geochelone radiata)
Order: Testudines, Family: Testudinidae
Ethiopian: Geochelone radiata only occur naturally in the extreme southern and southwestern part of the island of Madagascar. G. radiata have also been introduced to the nearby island of Reunion.
I. GEOGRAPHIC RANGE
II. PHYSICAL CHARACTERISTICS
- Ethiopian: Geochelone radiata only occur naturally in the extreme southern and southwestern part of the island of Madagascar. G. radiata have also been introduced to the nearby island of Reunion.
III. FOOD HABITS
- Growing to a carapace length of up to 16 inches and weighing up to 35 pounds, G. radiata is considered to be one of the world's most beautiful tortoises. G. radiata 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 G. radiata is brilliantly marked with yellow lines radiating from the center of each dark plate of the shell, hence the name radiated tortoise. This "star" pattern is more finely detailed and intricate than the normal pattern of other star-patterned tortoise species, such as G. elegans of India. G. radiata 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. There is slight sexual dimorphism. Compared to females, male G. radiata usually have longer tails and the notch in the plastron beneath the tail is more noticeable.
- G. radiata is an herbivore. Grazing makes up approximently 80-90% of their diet. They feed during the day primarily on grasses, fruit, and succulent plants. A favorite food in the wild is the Opuntia cactus. In captivity G. radiata is known to eat sweet potatoes, carrots, apples, bananas, alfalfa sprouts, and melons. According to some sources G. radiata seem to be partial to red foods. 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.
- Males first mate upon attaining lengths of about 12 inches; females may need to be a few inches longer. The male begins this fairly noisy procedure by bobbing his head and smelling the female's hind legs and cloaca. In some cases the male may lift the female up with the front edge of his shell to keep her from moving away. The male will then proceed to mount the female from the rear while striking the anal region of his plastron against the females carapace. Hissing and grunting by the male during mating is common. Females lay from 3 to 12 eggs in a pre-excavated hole 6 to 8 inches deep and then depart. Incubation is quite long in this species, lasting usually between 145 and 231 days. Juveniles are between 32 to 40 mm upon hatching. Unlike the yellow coloration of the adults, the juveniles are a white to an off-white shade. Juveniles attain the high-domed carapace soon after hatching.
- G. radiata prefer dry regions of brush, thorn (Diderae) forests and woodlands of southern Madagascar.
- Unfortunately, G. radiata is severely endangered due to loss of habitat, being poached for food, and being over exploited in the pet trade. G. radiata is listed in Appendix I of the Convention on International Trade in Endangered Species (CITES) which prohibits the import or export of the species under most conditions. However, due to the poor economic conditions of Madagascar, many of the laws are largely ignored. No estimates of wild populations are available, but their numbers are declining, and many authorities see the potential for a rapid decline to extinction in the wild. In the North American stud book, 400 specimens are listed as participating in captive breeding programs such as the Species Survival Plan in zoos. Captive breeding of G. radiata has shown great promise.