Researchers have been wondering how the iguanas reached Fiji. Most modern iguanas live in the Americas. Thousands of miles and one huge ocean.
They may have thought that volcanic activity ran there through Asia and Australia before pushing Fiji's islands far away.
However, new research shows that millions of years ago, iguanas pulled 5,000 miles of Odyssey into large quantities of floating vegetation, namely uprooted trees and small vegetation blocks. The journey is considered a record. Even more than the vertebrates living in other lands have traveled the sea before.
Scientists believe the iguanas were the way they reached the Galapagos Islands off the coast of Ecuador and the Caribbean islands. Initially they thought Fiji might be a little too far for such a trip, but in a new study, researchers tested genes in 14 iguana species ranging from the United States, the Caribbean and Fiji. They discovered that Fijian iguanas are most closely related to North American desert iguanas, with two groups splitting 31 million years ago.
Researchers created statistical models using that information and other data on where the iguanas live today and how they spread. The iguanas suggested that they most likely floated from North America to Fiji.
“Their results are overwhelmingly the most supportive of what we know now,” said Kevin de Queiros, an evolutionary biologist at the Smithsonian National Museum of Natural History, who is not involved in new research.
The study was published on Monday in the journal Proceedings, the National Academy of Sciences.
It may have taken a few months to travel from North America to Fiji, but these desert iguanas were ideal passengers as they were proficient at resisting dehydration and were able to snack on plants under their feet.
“If you have to choose vertebrates to survive a long trip on a raft across the ocean, then you'll have one iguana,” Simon Scarpetta, research author at the University of San Francisco, said in an email.
Many Fijian iguana species are at risk, with invasive green iguanas roaming the island today, said Robert Fisher, a research author of the US Geological Survey. Understanding where these creatures come from allows scientists to be equipped with tools to better protect them in the future.
