It looks like it’s drunk: the miniature frog pushes itself off the ground, jumps, then spins in the air, slams its head on the ground and lies on its back with its limbs outstretched before finally getting to its feet. And it is not an isolated case: the tiny anuras of the genus brachycephalus from Brazil have the smallest known semicircular canals in the inner ear among adult animals and are therefore unable to control their posture before landing, reports a research team led by Richard Essner from Southern Illinois University Edwardsville in the US in the journal Science Advances.
The semicircular canals are important for balance, specifically for sensing rotational acceleration. To measure and compare them more closely, the group used scans to create 3D casts of the inner ear of 147 species of frogs and toads, ranging from the largest to the smallest living species. Then she analyzed the jumps of 74 frogs from four species of the genus brachycephalus. The researchers focused on three individuals of the species Brachycephalus pernix. During the flight phase of the jump, they had difficulty keeping their balance.
The researchers suspect that the animals’ reduced sense of balance also influences other behaviors, such as eating and locomotion. This could put the frogs at greater risk from predators. The group therefore expects the tiny frogs to have other strategies to defend themselves. Such are frogs of the genus brachycephalus Although clumsy hoppers, they can disguise themselves and wear bone plates or warning colors. In addition, some of them are toxic, such as the species Brachycephalus rotenbergawhich possesses a powerful neurotoxin.