There are many theories as to how the crested iguana reached Fiji. One such theory is that millions of years ago, the ancestors of Fiji's Crested Iguana set out on an unplanned journey to an un-chosen destination. Scientists speculate that they could have arrived in the South Pacific from the Americas on massive rafts of floating vegetation on a course determined by the South Equatorial Current. As a result of this 12,000 kilometer journey, crested iguanas could be the most geographically isolated of all iguanas. But how was such an extraordinary voyage possible?

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. To dispel the drying effects of saltwater, they can actually sneeze salt through their noses! 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. Slowly, their colors became more like their surroundings; sea-toned aqua blue patches now mixed with their green skin, and white stripes like the breaking surf helped hide them among the palm fronds. The first raft-dwellers were large land iguanas, giants compared to present-day crested iguanas. However, over many, many generations, smaller versions, the crested and banded iguanas, evolved to take advantage of niches in their new habitat. Small-bodied iguanas could reach the tops of trees.

At the end of the Ice Age 18,000 years ago, the sea level slowly rose, and the family of Pacific iguanas found themselves even more isolated on increasingly smaller islands; the former mountain tops of larger landforms. The first humans arrived on Fiji and Tonga 3,000 years ago and it was a major catastrophe for the ancestral land iguanas. Archeologists have found all that remains of them; charred bones full of cut marks. As their smaller relatives watched from the treetops, the giant Pacific land iguanas were hunted to extinction within a few generations.

The crested iguana is a much more primitive species than its more modern cousin, the banded iguana. It is also much more rare, being found only on the dryer islands of Fiji.
The Crested iguana is also the larger of the two and bears the strongest family resemblance to the long-lost ancestors in Central America. In terms of its extraordinarily long voyage and millions of years in the remote islands of the Pacific, the magnificent crested iguana is certainly the world's greatest castaway. Or is it?