Imagine a hurricane over Central America's coast. Torrential rains and wind bring down a mountain landslide. A tangled mess of trees and vines, trapping the animals within, tumbles down into a raging river. They ride the river out to the ocean, drifting far from land and are collected by the South Equatorial current. Raft mates of the iguanas were mice, skinks, and spiders.
Weeks float into months and most of the castaways perish.
However, the iguanas are specially adapted for life at sea. Their thick skins protect against dehydration in the hot sun. Moreover, because they are vegetarians, their floating tree-raft doubles as dinner. Nevertheless, surviving the long journey to a foreign shore was just the beginning. During the millions of years before the arrival of man in Fiji and Tonga, the ancestral iguanas began to evolve to suit their new island homes.