Sea turtles can carry more than 100,000 tiny animals on their shells

Studying the diverse and abundant creatures that live atop loggerhead sea turtles could help scientists track and better understand the reptiles.


A loggerhead turtle grazes on sea grass. In stirring up the sea floor, the animals can pick up tens of thousands of tiny hitchhikers—small animals such as nematodes, crustaceans, and hydroids.

Loggerhead sea turtles migrate thousands of miles through the world’s oceans, but they don’t travel solo—research shows they carry surprisingly diverse and abundant populations of tiny creatures on their shells.

A new paper published May 20 in the journal Diversity shows that loggerhead sea turtles carry an average of 34,000 individual meiofauna—tiny organisms smaller than one millimeter—on their backs. One loggerhead carried nearly 150,000 individual animals on its shell, including nematodes, crustacean larvae, and shrimp.

“There literally is a [whole] world on there,” says Jeroen Ingels, a marine ecologist at Florida State University. It’s wild to find “that kind of diversity on another organism.”

Ingels and his team discovered more than a hundred new species of meiofauna, mostly nematodes, that hadn’t previously been found on loggerheads or other turtles. The team made their findings examining 24 loggerheads that arrived at St. George Island, Florida, in June 2018.

It was previously known that turtles carried some hitchhikers—but this quantity and degree of diversity hadn’t been seen before, Ingels says.

Studies of these tiny hitchhikers may help researchers trace the travels of...

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