Lush vegetation covers much of the land. Along the coast there are mangrove forests, pandanus, Barringtonia, hibiscus, and strand vegetation, commonly found throughout the Pacific. The adjacent lowland forest, which originally stretched inland over the lower slopes of the mountains, has been cut down extensively on Upolu and in more limited areas on Savai'i. Inland and at higher elevations, the rain forests contain trees and lianas of many genera and species. The higher elevations of Savai'i contain moss forest and mountain scrub.
Fifty species of birds are found; 16 of these are seabirds, many of which visit Samoa only during the breeding season. Sixteen of the 34 species of land birds are indigenous. Among the latter are small doves, parrots, pigeons, and wild ducks. The most interesting bird, scientifically, is the tooth-billed pigeon ( Didunculus strigirostris Peale ), which some ornithologists regard as the connecting link between bird life of the present and the tooth-billed birds of zoological antiquity.
The only indigenous mammals in Samoa are the rat ( Mus exulans Peale ) and the flying fox ( Pteropus samoensis Peale ). Numerous species of birds and mammals, chiefly domesticated, have been introduced by the Samoans and Europeans. Two species of snakes, several different lizards, and the gecko are found. Insect life includes many species of moths, beetles, spiders, and ants. The mosquito ( Stegomyia pseudoscutellaris ) is a carrier of human filaria.