Flea frog Brazil, scientifically known as Brachycephalus pulex, belongs to the group of amphibians and vertebrates. With a length of only about 7 to 8 mm, its extremely small size makes it the center of attention in the scientific community. The discovery of this frog, smaller than a human flea, makes it the smallest vertebrate in the world.

More than a decade later, a team led by Mirco Solé published an in-depth study on this frog species, which is difficult to capture and only found on two forested slopes in Bahia, Southern Brazil. This research suggests that the Brazilian flea frog is likely to be a candidate for the title of "smallest vertebrate in the world".

In the latest research, researchers conducted another expedition to the habitat of Brazilian tick frogs with the aim of capturing more specimens. They measured the frogs, examined their gonads to assess the level of sexual maturity, and checked if they had vocal sacs that are only possessed by male frogs.

After conducting a series of observations, researchers found that male frogs have a length of more than 7 mm, while female frogs have slightly larger sizes, specifically slightly above 8 mm. The smallest adult specimen successfully measured during the study had a length of 6.45 mm, indicating a size decrease of 30 percent compared to the smallest frog ever observed previously.

Because of its very small size, the Brazilian flea frog cannot control its vestibular system well to maintain balance, so they tend to lose stability when jumping from the ground.