An Amazonian frog has a secret weapon that protects it from being attacked by ants: It gives off a chemical scent that makes the ants think it's one of them.
The discovery was made by scientists from Brazil's National Institute of Amazonian Research, and details of the research have just been published in the journal Behavioral Ecology and Sociobiology. Mimicry is not unusual in the animal kingdom, whether it's spiders pretending to be ants, birds looking like caterpillars, or wild cats sounding like their prey. But scent mimicry of this kind is rarely seen in vertebrates, the scientists note.
The frog with the special scent is Lithodytes lineatus, which makes its living primarily in the Amazon region of South America. It does so completely free of attack by leaf-cutting ants that live in its midst.
RELATED: More Than 300 Spiders Pretend to Be Ants
Leaf-cutters - big for ants, with colonies that can total 1 million members - use chemical odors for both communication and recognition of their own kind. The researchers began with the idea that L. lineatus may well be slathered in a scent that fools the ants into letting the frog live in peace.
(Brief aside: Fans of The Walking Dead will recognize a similar strategy sometimes employed by Rick and the gang, who learned back in Season 1 that if they slather themselves in zombie blood and entrails they can move quietly among the, well, walking dead without being harmed. Of course, this frog doesn't have to do any slathering. It's naturally slathered.)
To test the notion, the scientists performed two experiments. First, they put L. lineatus in a glass enclosure along with four similar frog species and then watched what happened when leaf-cutting ants were allowed in with them. L. lineatus was not bitten by the ants and the frog did not even try to get out of the enclosure. The four other frogs, meanwhile, were quickly attacked. (The researchers wrote that the test frogs were not left in the enclosure long enough to be harmed and were released back into the wild without injury.)
Next, the team covered 20 of another species of frog with either skin extract from L. lineatus or ultrapure water and watched as not one of the frogs covered with the extract was set upon by a belligerent ant army. The water-covered frogs were, however, attacked.
"It therefore seems that Lithodytes lineatus has chemical skin compounds that are recognized by ants of genus Atta, which may allow for coexistence between ants and frogs," said study lead André Barros in a statement.
Nice work, Lithodytes lineatus.
WATCH VIDEO: Warm-Blooded vs. Cold-Blooded: What's The Difference?