A Very Tiny Frog

How small can a vertebrate get? The Brazilian flea toad (brachycephalus pulex) is the smallest known amphibian and the smallest known vertebrate. Despite its name, it isn’t a flea or a toad but a frog. This very tiny frog is small enough that two of them could sit side-by-side on your pinkie fingernail. From snout to rump, the males average about 7 millimeters and the females 8 millimeters. 

The Brazilian flea toad’s name can be misleading. These frogs were actually discovered and named in 2011, but it wasn’t until a decade later that they were studied in detail. While both toads and frogs are amphibians, there are some key differences. Toads have drier, bumpier skin and are typically found in dry environments, while frogs have smoother, more moist skin and tend to live near water.

Brazilian flea toads have a bright yellow-orange color, which is probably an aposematic signal to potential predators. Aposematism in animals is often a warning that their skin may contain toxins that make them unpleasant or dangerous to eat. A creature this small needs some way to protect itself.

Why would such a very tiny frog exist? They are endemic to a few forested hills in the southern coastal area of Brazil. Researchers have not studied them enough to understand the niche they fill in their environment, and studying such creatures as this very tiny frog is challenging. Luci Kirkpatrick of Bangor University in North Wales said that tiny creatures are “ecosystem engineers” that are “critical in making sure the food web functions properly.” 

God created an ecosystem with organisms that allow life to exist in a balanced environment on Earth. The very tiny frog known as the Brazilian flea toad can teach us a lot about the small world that sustains us.

— John N. Clayton © 2024

References: earth.com, mymodernmet.com, bbc.com, and onlinelibrary.wiley.com