The Hawaiian Islands are made up of a chain of ancient volcanic islands that have formed at irregular intervals over the last ten million years. There are over 100 islands in the chain, eight of which are considered major. Of the eight major islands, Kauai is the oldest, and the island of Hawaii is the youngest, having formed within the past million years. This vast discrepancy in age has contributed to the tremendous biodiversity that has evolved there. The other factor responsible for Hawaii's great species diversity is the island chain's remoteness. The nearest continent is 2,400 mi (3,862 km) away, thus limiting the total colonization that could, or has, taken place. The niches available to these colonizing species are very diverse due to geophysical events. For example, on the island of Kauai, the average annual rainfall on the windward side of Mount Waialeale is 460 in (1,169 cm), whereas on...