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Scientists think they’ve finally figured out how iguanas got to Fiji

Most modern-day iguanas live in the Americas – thousands of miles and one giant ocean away from the collection of remote Pacific islands

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A female Lau banded iguana in Fiji. Photo: US Geological Survey/AP
Associated Press
Researchers have long wondered how iguanas got to Fiji, a collection of remote islands in the South Pacific. Most modern-day iguanas live in the Americas – thousands of miles and one giant ocean away.
They thought maybe they scurried there via Asia or Australia before volcanic activity pushed Fiji so far away.

But new research suggests that millions of years ago, iguanas pulled off the 8,000km (5,000-mile) odyssey on a raft of floating vegetation – masses of uprooted trees and small plants. That journey is thought to be a record – further than any other land-dwelling vertebrate has ever travelled on the ocean.

The journey from North America to Fiji could have taken a few months, but desert iguanas would have been ideal passengers. Photo: Handout
The journey from North America to Fiji could have taken a few months, but desert iguanas would have been ideal passengers. Photo: Handout
Scientists think that’s how iguanas got to the Galapagos Islands off of Ecuador and between islands in the Caribbean. Initially they thought Fiji might be a bit too far for such a trip, but in a new study, researchers inspected the genes of 14 iguana species spanning the Americas, the Caribbean and Fiji. They discovered that Fijian iguanas were most closely related to desert iguanas from North America, and that the two groups split off around 31 million years ago.

The researchers created a statistical model using that information and other titbits about where iguanas live today and how they may spread. It suggested that the iguanas most likely floated to Fiji from North America.

“Given what we know now, their result is by far the most strongly supported,” said Kevin de Queiroz, an evolutionary biologist at the Smithsonian National Museum of Natural History, who was not involved with the new study.

If you had to pick a vertebrate to survive a long trip on a raft across an ocean, iguanas would be the one
Simon Scarpetta, study author

The research was published on Monday in the journal Proceedings of the National Academy of Sciences.

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