Tropical islands often harbor invertebrates, such as crabs and insects, as well as a variety of birds. Some tropical islands are even home to reptiles, amphibians or large mammals. The animals that inhabit tropical islands vary based on the island’s location, how far it is from land, whether or not people visit the island and the island’s geological history.
The island of Krakatoa provides an excellent example of the process by which animals colonize a tropical island. On the morning of August 27, 1883, the volcanic island erupted violently. The eruption, which was massive enough to alter the planet’s average temperature for a period of five years, exterminated virtually every living creature on the island. However, over the following months and years, animals reclaimed the territory.
Since its eruption, reptiles, mammals, birds and invertebrates have recolonized the island. The various species arrived via different means. Spiders used threads of silk to help lift them into the air, and the wind eventually brought them to the island. Birds and bats flew to the island from neighboring-island forests. Commensal rodents and insects likely arrived on the island as stowaways on ships and planes.
Islands that are close to major landmasses contain more animals than those in the middle of the ocean. Additionally, islands that lie in the path of ocean currents are home to more animals that use logs and other debris to travel from the mainland to the island.