A native green iguana on Fiji. For years, biologists puzzled over how these iguanas had ended up in the South Pacific, so far from other iguana species. A new study sheds light on their evolution.
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Where did the Fijian iguanas come from ... and how?
For decades, it's been a scientific mystery.
Most iguanas are indigenous to the Americas; however, native Fijian iguanas, call an island nearly 5000 miles away from their closest relatives in the South Pacific home.
Thanks to genome mapping, researchers think they've found out how: The iguanas rafted.
Biologists used phylogenomic data to essentially build an iguana family tree — seeing which species were most closely related to one another.
"The iguanas that live on Fiji were most closely related to a group of iguanas that I knew very well from the United States called desert iguanas," says Simon Scarpetta, an evolutionary biologist at the University of San Francisco who led the study.
This rafting theory isn't entirely unprecedented.
In the 1990s, after hurricanes Luis and Marilyn hit the Caribbean, researchers found that a group of iguanas had floated over 180 miles away from the Caribbean island of Guadeloupe to the territory of Anguilla — all on a clump of downed trees.
Reaching Fiji would have been nearly 30 times as far — a months-long journey of thousands of miles. But, the scientists who study these creatures say that if any creature could survive, it's iguanas.
Want to hear more about iguanas? Or rafts? Or evolutionary biology? Email us atshortwave@npr.org.
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This episode was produced by Hannah Chinn and edited by our showrunner Rebecca Ramirez. Jon Lambert and Tyler Jones checked the facts. The audio engineer was Zo vanGinhoven.