Tiny Brazilian frogs are poor jumpers because their ear canals are too small

Bob Yirka is a research scientist at Phys.org.

Pumpkin toadlets can't jump because their inner ear canals are too small. The group describes their study in a paper published in Science Advances. Pumpkin toadlets are too small to be able to land gracefully, according to the researchers.

Pumpkin toadlets are native to parts of Brazil and are known for their terrible landings after jumping. They don't attempt to orient themselves after jumping into the air and crashing into the ground. The researchers suspected that their troubles may lie with the inner ear and conducted a study of the canals of the toad and frog.

Animals have an inner ear canal filled with liquid. Nerve cells in the canal are stimulated as the animal moves. It gives a sense of balance.

Pumpkin toadlets had the smallest canals of all the creatures studied. Slow- motion videos produced by their high-speed cameras showed that the smallest frog in the group was the lowest in rotation speed. Creatures that jump need high rotation speeds to give them time to orient themselves. Pumpkin toadlets were similar to toads with impaired inner ear canals.

As the ear canal became smaller, it became harder for it to jiggle and flow, making it less of a sensation of balance. The ability to rotation is reduced in the frog. Because the frog still exists, it must have developed some other means of self-preservation, such as developing toxic skin, camouflage or even thicker skin, according to the researchers.

More information: Richard L. Essner et al, Semicircular canal size constrains vestibular function in miniaturized frogs, Science Advances (2022). DOI: 10.1126/sciadv.abn1104 Journal information: Science Advances

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