Iguanas Travelled 5,000 Miles to Fiji on Rafts 34 Million Years Ago

A new study suggests that iguanas crossed over 5,000 miles from North America to Fiji around 34 million years ago by clinging to rafts of floating vegetation. The journey, considered the longest-known transoceanic migration by a terrestrial species, is believed to have occurred shortly after Fiji's islands formed. Researchers speculate that extreme weather events, such as cyclones, could have uprooted trees and carried iguanas across the Pacific. The reptiles, which are the only iguanas found outside the Western Hemisphere, have long been a subject of debate regarding their origins.

Genetic Study Reveals Direct Link to North America

According to the study published in PNAS, researchers found that Fiji's iguanas share a closer genetic link with species from North America than previously thought. Simon Scarpetta, Assistant Professor of Environmental Science at the University of San Francisco, stated in a press release that the evidence supports a direct journey from the West Coast of the United States to Fiji. This challenges earlier theories suggesting the reptiles may have arrived via Antarctica or Australia.

Reportedly, Jimmy McGuire, Professor of Biology at the University of California, Berkeley, said that alternative explanations for their migration did not fit within the geological timeline. It was noted that the iguanas likely reached Fiji soon after land became available in the region.

Adaptations May Have Helped Survival

More than 200 museum specimens were analysed for the research. The findings indicated that the Fijian iguanas, classified under the Brachylophus genus, are closely related to the Diposaurus genus, which includes desert iguanas found in North America. Scarpetta explained that these lizards are highly resistant to starvation and dehydration, which may have increased their chances of surviving the journey.

The estimated timeline of their migration aligns with the formation of Fiji's islands. Researchers suggest that once land appeared, the iguanas established themselves, highlighting the remarkable nature of their journey.