These miniature Brazilian frogs (aka pumpkin toadlets) don't have much balance and thus jump in reallllly awkward ways. Apparently, their inner ears are too small to provide good balance. New research published in Science explains the phenomenon:
Miniaturization has evolved repeatedly in frogs in the moist leaf litter environments of rainforests worldwide. Miniaturized frogs are among the world's smallest vertebrates and exhibit an array of enigmatic features. One area where miniaturization has predictable consequences is the vestibular system, which acts as a gyroscope, providing sensory information about movement and orientation. We investigated the vestibular system of pumpkin toadlets, Brachycephalus (Anura: Brachycephalidae), a clade of miniaturized frogs from Brazil. The semicircular canals of miniaturized frogs are the smallest recorded for adult vertebrates, resulting in low sensitivity to angular acceleration due to insufficient displacement of endolymph. This translates into a lack of postural control during jumping in Brachycephalus and represents a physical constraint resulting from Poiseuille's law, which governs movement of fluids within tubes.
Smithsonian magazine further explains:
"They're not great jumpers, and they're not particularly good walkers either. They sort of stomp around in a stilted, peg-like version of walking," says Edward Stanley, study co-author and director of the Florida Museum of Natural History's Digital Discovery and Dissemination Laboratory, in a statement.
Using CT scans of the brightly colored toadlet, researchers found that their vestibular system, the structures within the ear that guide balance in vertebrates, is so small that when the frogs spring into the air, they quickly lose their balance and simply fall gracelessly to the ground, reports Isaac Schultz for Gizmodo. The CT scans were part of a larger project called oVert, a four-year initiative across 18 institutions to create 3-D models of more than 20,000 fluid-preserved museum specimens.
You can watch them in all of their awkward glory in the video embedded above. These tiny frogs really are quite pathetic and silly. I've never related so hard to an amphibian in all my life.