As a tortoise the most noticeable feature of the radiated tortoise is their large, smooth domed shell. This is coloured dark brown and is noticeable for the star like patterns of yellow lines which radiate out from the centre of each scale (scute). Some tortoises have been recorded that have an entirely yellow shell. There are blood vessels and nerves running through the shell which allow them to sense when it is touched.
Their head is at the end of a short neck which are both coloured yellow. The top of the head is black. They have short legs which end with rounded flat feet. At the back of the shell is a short tail.
Males and females can be distinguished in most cases through the male having a longer tail and a notch under the shell at the base of the tail.
Their shell may measure up to 41cm (16in) and they weigh 16kg (35lbs).
Radiated tortoises are herbivores. Most of their diet consists of grasses. They will also eat fruit and succulents with a favourite being cactus. On a rare occasion they may eat small amounts of meat.
Since the introduction of prickly pear cactus to Madagascar this has become a food source for radiated tortoises. When they eat this it leaves a red stain resembling lipstick around their mouth.
Most of their grazing takes place in the same areas as they prefer to graze on new growth.
They are capable of going long periods without water though will drink when water is available.
Average 32.8 years
Record 188 years
— AD —
Madagascar is the native home of the radiated tortoise. Here they can be found in the South of the island.
They have also been introduced to Reunion.
Radiated tortoises make their home in spiny forests, high plateaus, thorn forests, woodlands and sandy dunes.
They breed from February to April. During this period the males will wrestle in an attempt to flip their rival on to their back giving them an opportunity to mate with the females in that area.
Once the male finds a suitable mate he will bob his head and smell her hind legs. He will then begin to walk around her and bump her carapace. Following this he will commence mating which is extremely noisy with much hissing and grunting.
Following a successful mating the female will dig a nest that is 15-20cm (6-8in) deep in to which they deposit 3-12 eggs which are shaped like a ball. Once these eggs are laid the female will leave and these eggs hatch on their own. They have a long incubation at
Once they hatch the young are on their own and responsible for their own care. At hatching the young have white skin and measure 32-40mm (1.3-1.6in).
As they grow they develop rings on their scutes that can help identify the age of the tortoise.
Sexual maturity is tied to size and is achieved at 31cm (12in) for males and females being slightly larger to achieve this.
Radiated tortoises undertake their activities during day time.
During the warmest parts of the year they may dig a burrow to escape the heat and to decrease water loss.
They are primarily solitary but if there is an abundance of food in an area they may gather.
In rain they will raise their body up and wiggle it in a slightly comical display.
Predators and Threats
Humans are the main predator of the radiated tortoise. Their population has potentially dropped as much as 80% and they have disappeared from 40% of their range.
They are also threatened by habitat destruction including clearing of trees for agricultural land and to burn for charcoal.
In Madagascar they are often captured to place in poultry enclosures as it is believed they prevent a range of poultry diseases.
Another major threat is capture to be traded internationally both for the pet trade and to be used in traditional medicines.
An estimated 45,000 radiated tortoises are poached each year for the illegal wildlife trade.
In Madagascar the radiated tortoise is known as the sokake.
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