Radiated tortoise (Astrochelys radiata)

Synonyms: Asterochelys radiata, Geochelone radiata, Testudo coui, Testudo desertorum, Testudo hypselonata, Testudo radiata
French: Tortue Radiée De Madagascar, Tortue Rayonnée
Spanish: Tortuga Estrellada De Madagascar, Tortuga Rayada
GenusAstrochelys  (1)
SizeCarapace length: up to 40 cm (2)
Weightup to 16 kg (2)

The radiated tortoise is classified as Critically Endangered (CR) on the IUCN Red List (1), and listed on Appendix I of CITES (3).

The radiated tortoise (Astrochelys radiata) of Madagascar is one of the most attractive of all the tortoises. The high-domed, dark carapace is marked by brilliant yellow lines that radiate from the centre of each plate and create this tortoise's distinctive pattern (2). As individuals age, the dark pigment in the shell fades, producing a lighter coloured shell (4). The legs, feet and blunt-shaped head are also yellow in colour with the exception of a dark patch on the top of the head (2). Males can be distinguished by their longer tails and a notch in the under shell (plastron), below the tail (2). Juveniles are black and off-white when they hatch, but quickly develop the adult's striking colouration (2).

Endemic to Madagascar, the radiated tortoise is restricted to southern areas of the island (5).

Inhabits the dry thorn forests and tropical woodlands of southern Madagascar (2).

Males reach sexual maturity once they have attained a carapace length of around 30 cm (2). Rival males will fight during the breeding season and attempt to roll one another onto their backs. They initiate courtship by a head-bobbing display and smelling the female's hind legs. This is followed by energetic circling and butting of the female's carapace. Once mating has occurred, the female lays her clutch of 3–12 eggs in a nest dug into the ground (2). Eggs are laid at the end of the wet season, between February and April, and hatch after 10 months or more (4). Hatchlings emerge within a few weeks of one another at the onset of the next rains, in November or December (4).

Radiated tortoises graze on vegetation such as leaves and grasses, flowers, fruit and cacti (2). During much of the year dead leaves also make up a substantial part of their diet (4).

The island of Madagascar has suffered widespread habitat destruction as the land is cleared to make way for charcoal production and short-term unsustainable development (4). In addition to habitat loss, these striking tortoises are targeted by the international pet trade and are also captured for food in some areas (2).

International trade in radiated tortoises is prohibited by its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) (3). A number of conservation initiatives have recently begun under the jurisdiction of international conservation organisations such as the Wildlife Conservation Society (WCS) (4).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. IUCN Red List (October, 2009)
  2. Animal Diversity Web (September, 2003)
  3. CITES (September, 2003)
  4. Gibson, R. (2004) Pers. comm.
  5. World Turtle Database (September, 2003)