Naturalists found a tiny frog with a mushroom growing from its side( Credit: Lohit Y.T./ WWF-India/ CC-BY-SA-2.0)

In the summer of 2023, Lohit Y.T. and his team at the World Wildlife Fund-India traveled to the foothills of the Western Ghats in Karnataka, India. They hoped to research the area's amphibians and reptiles, which often emerge during the humid monsoon season. While documenting a cluster of about 40 Rao's intermediate golden-backed frogs near a small pond, the naturalists noticed something unusual. One of the amphibians had a mushroom sprouting from its side!

The tiny frog was perched at the center of a twig. The naturalists watched as it hopped to the tip. The amphibian turned around and changed positions several times. But the mushroom did not budge from its place. Mr. Lohit's team photographed the frog extensively without touching it.

Researchers believe the frog is growing a bonnet mushroom (Credit: Lohit Y.T./WWF-India/ CC-BY-SA-2.0)

"When I first observed the frog with the mushroom, I was amazed and intrigued by the sight," Mr. Lohit told CNN via email. "My thought was to document it, as this phenomenon is something we have never heard of."

The unusual discovery, revealed in the journal Reptiles and Amphibians on January 31, 2024, is puzzling scientists worldwide. Mushroom experts believe that the frog is housing a type of bonnet mushroom typically found on decaying wood and tree roots. However, they are unsure how the frog acquired its fungal friend.

Some researchers speculate the area's warm and humid weather, together with the frog's moist skin, may have provided ideal conditions for the mushroom to grow. Others think the mushroom could have grown from wood debris stuck under the frog's skin. However, neither theory can be confirmed without examining the amphibian.

The WWF-India team will revisit the area to see if they can find the frog again (Credit: Lohit Y.T./ WWF-India/ CC-BY-SA-2.0)

Mr. Lohit and his team plan to revisit the area this summer to look for the frog.

"If we manage to find it, it'll be great," Mr. Lohit said. "The spot has been frequented by many enthusiasts and experts alike. It would be great if some researcher gets their hands on it and can further the investigation, but again, it's all highly unlikely to happen."

Rao's intermediate golden-backed frogs are endemic to Southern India. They get their name from their orangish-brown color. The tiny amphibians grow to a maximum length of about 2.46 inches (6.24 cm). Golden-backed frogs thrive in a variety of habitats, including lakes, rivers, forests, and even rice fields.