Radiated Tortoise

Astrochelys (Geochelone) radiata
Geographic Range
Astrochelys radiata only occur naturally in the extreme southern and southwestern part of the island of Madagascar. A. radiata have also been introduced to the nearby island of Reunion (LPZ 1999).

Biogeographic Regions:
ethiopian (native ).

Habitat
A. radiata prefer dry regions of brush, thorn (Diderae) forests and woodlands of southern Madagascar (LPZ 1999).

Physical Description
Growing to a carapace length of up to 16 inches and weighing up to 35 pounds, A. radiata is considered to be one of the world's most beautiful tortoises. A. 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 A. 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. A. 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 A. radiata usually have longer tails and the notch in the plastron beneath the tail is more noticeable (Kirkpatrick 1992).

Some key physical features:
ectothermic ; bilateral symmetry .

Reproduction
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 (Kirkpatrick 1992).

Key reproductive features:
gonochoric/gonochoristic/dioecious (sexes separate).

Food Habits
A. 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 A. radiata is known to eat sweet potatoes, carrots, apples, bananas, alfalfa sprouts,

and melons. According to some sources A. 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 (Behler and Iaderosa 1991).



Quick facts

Name

•Astrochelys radiata
•Geochelone radiata
•Strahlenschildkröte - German
•Stralenschildpad - Dutch
•Strålsköldpadda - Swedish
•Sädekilpikonna - Finnish
•Tortuga estrellada de Madagascar - Spanish
•Tortue étoilée de Madagascar - French
Origin

•native to Madagascar, an island country east of Africa
Size

•up to 16 inches (40 cm)
•typical female size 9.5 - 14 inches (24.2 - 35.6 cm)
•typical male size 11 - 15.5 inches (28.5 - 39.5 cm)
•up to 35 lbs (16 kg)
•typical male weight 9.9 - 23 lbs (4.5 - 10.5 kg)
•typical female weight 6.8 - 22.5 lbs (3.1 - 10.2 kg)
•largest of the starred tortoises
Color & pattern

•high-domed carapace
•black with yellow, radiating lines
•pattern varies by the individual
•some are more black, some are more yellow
•coloring fades with age
•legs, feet and head are yellow
•a dark patch on the top of the head
Habitat

•dry thorn forests, thorny brush, tall grasses, woodlands
•dry regions with seasonal heavy rain
•prefers open habitats with low scrubs and grasses
Diet & Activity

•primarily herbivorous
•feeds on grasses and succulents
•most active during rains
•does not hibernate
Care

•highly prone to pyramiding
•considered to be a hardy species
•sexual maturity around 16 years of age, but usually grows faster in captivity
Conservation

Tidbits

•Per Gladys Porter Zoo in Texas, Radiated tortoises can live at least 200 years!
•Considered to be one of the most beautiful tortoises in the world.

Informative