Madagascar, officially the Republic of Madagascar (Malagasy: Repoblikan'i Madagasikara [republiˈkʲan madaɡasˈkʲarə̥]; French: République de Madagascar) and previously known as the Malagasy Republic, is an island country in the Indian Ocean, off the southeastern coast of Africa. The nation comprises the island of Madagascar (the fourth-largest island in the world), as well as numerous smaller peripheral islands. Following the prehistoric breakup of the supercontinent Gondwana, Madagascar split from India around 88 million years ago, allowing native plants and animals to evolve in relative isolation. Consequently, Madagascar is a biodiversity hotspot; over 90 percent of its wildlife is found nowhere else on Earth. The island's diverse ecosystems and unique wildlife are threatened by the encroachment of the rapidly growing human population.
Initial human settlement of Madagascar occurred between 350 BCE and 550 CE by Austronesian peoples arriving on outrigger canoes from Borneo. These were joined around 1000 CE by Bantu migrants crossing the Mozambique Channel. Other groups continued to settle on Madagascar over time, each one making lasting contributions to Malagasy cultural life. The Malagasy ethnic group is often divided into eighteen or more sub-groups of which the largest are the Merina of the central highlands.
Adansonia is a genus of eight species of tree, six native to Madagascar, one native to mainland Africa and the Arabian Peninsula and one to Australia. The mainland African species also occurs on Madagascar, but it is not a native of that island, and was introduced in ancient times to south Asia and during the colonial era to the Caribbean. A ninth species was identified in 2012, incorporating upland populations of southern and eastern Africa.
A typical common name is baobab. Other common names include boab, boaboa, tabaldi, bottle tree, upside-down tree, and monkey bread tree. The generic name honours Michel Adanson, the French naturalist and explorer who described Adansonia digitata.
Adansonias reach heights of 5 to 30 m (16 to 98 ft) and have trunk diameters of 7 to 11 m (23 to 36 ft). Glencoe baobab – an African baobab specimen in Limpopo Province, South Africa, often considered the largest example alive – up to recent times had a circumference of 47 m (154 ft). Its diameter is estimated at about 15.9 m (52 ft). Recently the tree split up into two parts and it is possible that the stoutest tree now is Sunland baobab, also in South Africa. The diameter of this tree is 10.64 m (34.9 ft), with an approximate circumference of 33.4 m (110 ft).