Radiated Tortoise Classification and Evolution
The radiated tortoise is a relatively large species of tortoise, natively found on the island of Madagascar. Although having evolved in similar environments to other star-patterned tortoises from around the tropics, the radiated tortoise has more striking and complex markings than those of the Indian star tortoise, for example. The radiated tortoise is also known as the Sokake in Madagascar, and although they are critically endangered in the wild, it is widely believed that they are the most beautiful of all tortoise species. Naturally then, they are a popular exotic pet, which is thought to be one of the main reasons for their demise.
Radiated Tortoise Anatomy and Appearance
The male radiated tortoise tends to be slightly larger than females and the two sexes are also easily identified as the tail of the male radiated tortoise is often substantially longer than that of the female. Radiated tortoises have high-domed, dark brown to black shells, covered with bright yellow or orange intricate star-like patterns. Unlike other star-patterned tortoises, the centres of the stars on the carapace of the radiated tortoise are not raised, giving their domed shell a smoother appearance. The legs, tail and head are a yellowish colour with a black spot on top of the head, which varies in size between individuals. The appearance of this tortoise actually camouflages it perfectly in the long grasses.
Radiated Tortoise Distribution and Habitat
The radiated tortoise is natively found on the island of Madagascar in the far south and south-western parts of the island. They inhabit dry regions of brush, thorn forests, tall grasses and woodland, with the whole population found in an area 10,000 km squared. Isolated populations can still be found on the higher plateaus as well, but these habitats are incredibly fragmented and the existence of the tortoise here is not thought to go on for much longer. The radiatedtortoise is thought to have disappeared entirely from around 40% of it's historical range, due to both habitat loss and exploitation.
Radiated Tortoise Behaviour and Lifestyle
Like many other tortoise species found around the world, the radiated tortoise generally leads a fairly solitary life, although it is not uncommon for a number to be found grazing together (particularly around the breeding season). They are incredibly adaptable to the changing seasons from dry and arid to the heavy rains of the monsoon, when they are said to almost dance in the rain to shake it off. Radiated tortoises also emit a loud screeching sound when startled to hopefully intimidate and then scare off the unwelcome predator. The radiated tortoise is a peaceful animal but will become aggressive towards individuals that it sees as a threat.
Radiated Tortoise Reproduction and Life Cycles
Radiated tortoises usually begin mating when they are around half their adult size, and it starts with the male bobbing his head up and down to court his female. Once mated, the female digs a nest in the ground where she lays up to 5 small eggs (although 10 ore more is not uncommon). After an incubation period of between 4 and 7 months, the young radiated tortoises hatch measuring between 3 and 4 cm. Although they are born with their detailed star-patterns, the markings are white until they grow older. Radiated tortoises usually live for 40 to 50 years, but some have been known to be more than 100.
Radiated Tortoise Diet and Prey
The radiated tortoise is a primarily herbivorous animal, and although the majority of it's diet is comprised of plant matter, they are known to supplement their nutrition by eating a small animal every now and again. Despite this, they need a high fibre and low protein diet to survive the most successfully. Leafy greens, grasses and herbs make up the bulk of the radiated tortoise's food, along with other plant matter like fruits, berries and prickly pears. In a book written abouttortoises from around the world, the radiated tortoise is said to be particularly partial to eating foods that are red in colour.
Radiated Tortoise Predators and Threats
In their natural habitats, these ground-dwelling animals are prey to a number of predators including snakes and large birds of prey. Radiated tortoises have a couple of defence mechanisms to try to protect them seeing that they can't run away, including making a loud screeching sound and the ability to pull their soft limbs and head inside their hard shells. Humans are however, the biggest threat to the radiated tortoise both through habitat destruction and exploitation. The radiated tortoise is commonly consumed and captured for the exotic pet trade.
Radiated Tortoise Interesting Facts and Features
The oldest living reptile was a radiated tortoise known as Tu'i Malila that was given to the Royal family in the mid 1700s by explorer Captain James Cook, and she died in 1965 at around 250 years old from natural causes. Although radiated tortoises are native to Madagascar, they have been introduced to the islandsof Reunion and Mauritius in the Indian Ocean to boost their tortoise populations. Despite the fact that many radiated tortoises are eaten in Madagascar, it is actually people coming from other parts of the island, as the local tribes living alongside radiated tortoises believe there is a taboo against both touching and eating them.
Radiated Tortoise Relationship with Humans
Humans are the biggest threat to radiated tortoises, from habitat destruction to their consumption. It is thought that remaining populations have seen an 80% reduction in numbers over just three generations and those inhabiting south Madagascar's higher plateaus are even worse affected. Despite the fact that the radiated tortoise is now one of the most protected tortoise species in the world, an estimated 45,000 are killed every year across the southern part of the island, just for food. The beauty of the radiated tortoise has also meant that they are in high demand in the illegal exotic pet trade.
Radiated Tortoise Conservation Status and Life Today
Due to a dramatic fall in population numbers, the radiated tortoise has been listed as being Critically Endangered and is therefore under severe threat from becoming extinct in the wild forever. However, captive breeding programs have been relatively successful and are crucial to the survival of this species in the future. Due to the laws about exporting listed species though, there are few found in captivity, most of which are in the USA where they were taken before the species was declared to be at imminent risk from extinction.