The country is home to some of the world's rarest plants and animals, but human habitation and the introduction of non-native species have threatened its indigenous flora and fauna. Due to its volcanic origin, age, isolation, and unique terrain, Mauritius is home to a diversity of flora and fauna not usually found in such a small area. Before the Portuguese arrival in 1507, there were no terrestrial mammals on the island. This allowed the evolution of a number of flightless birds and large reptile species. The arrival of humans saw the introduction of invasive alien species, the rapid destruction of habitat and the loss of much of the endemic flora and fauna. In particular, the extinction of the flightless dodo bird, a species unique to Maurtitius, has become a representative example of human-driven extinction. The dodo is prominently featured as a (heraldic) supporter of the national coat of arms of Mauritius.