Measuring less than one-half inch in body length, the Brazilian gold frog is a denizen of the Brazilian Atlantic rainforest belt. These tiny frogs inhabit the rainforest leaf litter, where they prey on very small invertebrates. Also called flea frogs, scientists thought that these tiny amphibians were the smallest frogs in the world until 2012, when they lost their title to an even smaller species, native to Asia.
Brazil's Atlantic Rainforest
So far, scientists have only documented Brazilian gold frogs in the state of Rio de Janeiro, Brazil. However, it's possible their range extends much farther than is currently thought. The Atlantic rainforest belt stretches all the way to Argentina and Paraguay, so it's possible these frogs -- which are easily overlooked because of their small size -- inhabit a larger range. Unfortunately, humans have cleared and altered much of this forest, and only 15 percent remains intact.
The Forest Floor
Brazilian gold frogs are creatures of the rich, rainforest leaf litter. Living in both primary- and secondary-growth forests, their coloration and small size make them extremely cryptic. These forests are extraordinarily diverse, and in some areas, scientists have found more than 250 tree species in about 2.5 acres of habitat. Leaf litter is a common microhabitat for frogs around the world, as it provides a very high humidity and abundance of prey.
Adaptations to Their Habitat
According to a 2011 study by Marlon Almeida-Santos, et al., published in the “Journal of Herpetology,” Brazilian gold frogs occur at relatively high densities. The team’s study concentrated on two different sites, and found as many as four frogs per 10,000 square feet, at the more densely populated of the two sites. The authors suggest that the frog’s reliance on very small organisms for food -- primarily mites and springtails -- and tiny size allow them to be so successful. Additionally, the frogs’ reproductive method may help them to achieve very high densities. Brazilian gold frogs exhibit direct development, in which the young develop without passing through a tadpole stage. This means that the frogs do not need to find water to reproduce, and can colonize areas without standing water.
Absent from Anthropogenic Habitats
While the frogs have a large range and appear to be locally abundant, their population appears to be trending downward because of habitat destruction. Herpetologists have never recorded Brazilian gold frogs living in human-altered habitats; instead, they appear to be restricted to high-quality forest habitats. Despite this, the IUCN Red List of Threatened Species classifies Brazilian gold frogs as a species of “least concern.”
- The Nature Conservancy: Brazil Atlantic Forest
- Journal of Herpetology: Ecology of the Brazilian Flea Frog Brachycephalus Didactylus (Terrarana:Brachycephalidae)
- SDB Core: Direct Development in Frogs
- Frogs are Green: One of the Smallest Frogs in the World Discovered
- Time.com: Smaller than a Dime, the World’s Tiniest Frog Has Been Discovered Read more: Smaller Than a Dime, World's Tiniest Frog Is Discovered
- AmphibiaWeb.org: Brachycephalus Didactylus
- The IUCN Redlist of Threatened Species: Brachycephalus Didactylus
- Ryan McVay/Photodisc/Getty Images