Grape-Doling Tourists Gave Endangered Iguanas High Blood Sugar

Research finds that a high-sugar diet supplied by tourists is giving Bahamian rock iguanas the lizard equivalent of high blood sugar.

Written byDan Robitzski

| 3 min read

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A Northern Bahamian Rock Iguana cranes its neck to eat a grape that’s speared on the end of a stick.

Researchers previously recommended iguanas be fed grapes instead of bread and that the fruit be skewered on a stick to prevent the animals from ingesting sand.

Image credit:© ISTOCK.COM, JANALYNN

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Northern Bahamian rock iguanas (Cyclura cychlura), already listed as vulnerable on the International Union for Conservation of Nature’s Red List, face a grave new threat: adoring tourists who regularly offer them grapes as if they’re paying tribute to Dionysus, the Greek god of wine.

Research published today (April 21) in the Journal of Experimental Biology shows that iguanas that live on islands frequented by grape-slinging tourists are unable to regulate their blood glucose levels as well as those that live on more remote islands to which humans rarely venture. The study focused on two subspecies of the rock iguana—the Allen Cays rock iguana (ssp. inornata) and the Exuma rock iguana (ssp. figginsi)—both of which are critically endangered.

“I think this is an important model that allows us to test for these effects because this is going on for wildlife across the planet. . . in other tourist settings,” lead study ...

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Meet the Author

Dan Robitzski
Dan is an award-winning journalist based in Los Angeles who joined The Scientist as a reporter and editor in 2021. Ironically, Dan’s undergraduate degree and brief career in neuroscience inspired him to write about research rather than conduct it, culminating in him earning a master’s degree in science journalism from New York University in 2017. In 2018, an Undark feature Dan and colleagues began at NYU on a questionable drug approval decision at the FDA won first place in the student category of the Association of Health Care Journalists' Awards for Excellence in Health Care Journalism. Now, Dan writes and edits stories on all aspects of the life sciences for the online news desk, and he oversees the “The Literature” and “Modus Operandi” sections of the monthly TS Digest and quarterly print magazine. Read more of his work at danrobitzski.com.
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