Astrochelys radiata

Radiated Tortoise

Pale lines spread out across each shell scute like rays of light.

Reference photo, not the individual on display. Credits appear below.

Care commitment Specialist setup

Habitat Ground & cover

Visiting Watch quietly

Meet your new acquaintance

Nickname Sunburst Shell

Diurnal and terrestrial

The name describes lines radiating from the centres of the shell scutes. It has nothing to do with radioactivity.

Species stories

A long-lived guest of Tonga’s royal household

Tu’i Malila lived with Tonga’s royal household. San Francisco Zoo records the 1953 royal visit and its death in 1966, with longevity commonly estimated at 188 years.

The account of a gift from Captain Cook is traditionally attributed rather than equally documented. Early origin, estimated age and later witnessed events have different evidential strength.

The story remains powerful without flattening those distinctions: a tortoise can span generations of human memory, introducing a timescale far beyond a short-term idea of keeping an animal.

Story sources:

San Francisco Zoo · Radiated tortoise

At a glance

Radiated tortoises are native only to southern and southwestern Madagascar, using dry scrub and spiny woodland and feeding mainly on plants. “Radiated” describes yellow lines extending across the shell scutes, not radioactivity, and not every star-patterned tortoise is this species.

Plants, sunlight and retreat choices shape a terrestrial day. Nesting and small hatchlings connect the adult outline to gradual growth.

Radiating lines do not identify every star-patterned tortoise as this species, and the shell is a living structure. Its beauty belongs beside native habitat, development and human history, broader than any one famous individual.

Common names Radiated Tortoise; Astrochelys radiata

Scientific name Astrochelys radiata

Native rangeSouthern and southwestern Madagascar

Adult sizeOften about 30–40 cm shell length

ActivityDiurnal and terrestrial

Diet Offer varied suitable grasses, herbs, leaves and other fibrous plants, coordinated with calcium, lighting and water. Large fruit portions, meat and energy-rich foods should not dominate.

Habitat & care

Provide warm, ventilated ground space, UVB, drinking water and a suitable plant-based diet, with cooler shelter available.

Values guide routine care, not breeding or brumation. Dimensions are length × width × height for one adult unless stated otherwise; larger animals need more space.

TemperatureBasking surface 35–40°C A starting band within JZAR’s broader basking range; daytime air 28–32°C, night 24–28°C, with cooler retreats.

HumidityAbout 50%+ The cited breeder’s indoor reference floor; retain locally moist lower substrate and assess juveniles separately.

LightingUVB & shade Choose UVB intensity and distance for the species, with a fully shaded retreat.

Space250×150×60 cm Recommended adult indoor starting recommendation; provide a larger safe paddock where possible, with shade and heated shelter.

Look a little closer

Find the centre of a scute and trace one yellow ray to its edge, then compare the neighbouring pattern. Look beneath the shell at how the legs lift and support it. Movement changes how the radiating lines appear across the curved shell.

Care note: Learning about its origin and native habitat is part of meeting the species.

About this profile

Size ranges are reference values; sex, origin and age affect appearance.

Profile status: Reference profile · Reviewed 2026-10-20

References (6)

Photo: Source: https://commons.wikimedia.org/wiki/File:Astrochelys_radiata_-Roger_Williams_Park_Zoo,_USA-8a.jpg CC BY 2.0 · Original image, credit and licence

Behaviour notes describe the species, not a promise about every individual. These care notes introduce its needs; ask our team about the animal on display and any supervised encounters.