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World’s Smallest Frog Discovered

Friday, January 13th, 2012

Researchers have discovered two species of what may be the world’s smallest frog species. As described in the journal PloS ONE, these new species of mini, terrestrial frogs were found on the island of New Guinea, and represent not only the smallest known frog but possibly also the smallest known vertebrate species (animal with a backbone). Both new species are members of the recently described genus Paedophryne, the four species of which are among the ten smallest known frog species. They attain an average body size of only 7.7 mm (range 7.0–8.0 mm), less than the size of an M&M.

Photo courtesy Louisiana State University/PloS ONE

The researchers believe that the frogs have evolved their teeny size in a unique ecological niche: the leaf litter of tropical forests that remains moist year round. The frogs eat even tinier creatures (mites etc) that most other frogs don’t exploit. They are well camouflaged among leaves on the forest floor, and have evolved calls resembling those of insects.

According to the researchers, other places in the world that also feature dense, moist leaf litter tend to possess such small frog species, indicating that amphibians are well placed to occupy this ecological niche.

Before the Paedophrynes were found, the title of “world’s smallest frog” was bestowed on the Brazilian gold frog (Brachycephalus didactylus) and its slightly larger Cuban relative, the Monte Iberia Eleuth (Eleutherodactylus iberia). They both measure less than 1cm long.

For more information:

Rittmeyer EN , Allison A , Gründler MC , Thompson DK , Austin CC , 2012 Ecological Guild Evolution and the Discovery of the World’s Smallest Vertebrate. PLoS ONE

Tags: amphibian ecology, earth's smallest frog, earth's smallest vertebrate, frog discoveries, frogs Papua New Guinea, miniature frogs, newly discovered amphibians, Paedophryne, Rainforest Frogs, world's smallest frogs
Posted in Amphbian research, Frogs and the Rainforest, Life Cycle of Frogs, Uncategorized, newly discovered frogs | No Comments »

Winter is Coming: How Do Frogs Avoid Freezing?

Sunday, October 9th, 2011

Yesterday while shopping at the mall, I noticed that some stores had already begun putting up holiday decorations. The racks were filled with sweaters and down coats. We humans (at least in the northeast U.S.) are preparing for winter. But what about our amphibian friends? How do they prepare for winter? After all, frogs would seem vulnerable to extreme cold with their thin skins and their need to constantly stay moist.

Actually, we don’t need to worry about the frogs. They are well-equipped to deal with the cold weather, even with Arctic temperatures.

Frogs are ectothermic, which means that they rely on their environment to regulate their body temperature. Birds and mammals, including humans, are endotherms. We generate heat chemically and internally by breaking down food. The bodies of ectotherms reflect the air, ground, and water temperatures around them. One advantage that ectotherms have over mammals is that they can survive for long periods without eating.

In the fall, frogs first need to find a place to make their winter home, a living space called a hibernaculum that will protect them from weather extremes and from predators. The frog then “sleeps” away the winter by slowing down its metabolism. When spring arrives, it wakes up and leaves the hibernaculum, immediately ready for mating and eating.

Aquatic frogs and toads such as the leopard frog and American bullfrog usually hibernate underwater in streambeds or on pond bottoms. Because aquatic frogs need oxygen, they lie just above the mud, or only partially buried in the mud, so they are near the oxygen-rich water. They may even occasionally slowly swim around.

Terrestrial frogs and toads typically hibernate on land. Those frogs and toads that are good diggers like the American toads burrow deep into the soil, safely below the frost line. Other frogs, such as the wood frog and the spring peeper, aren’t good diggers and so must scout out their winter homes in deep cracks and crevices in logs or rocks, or they might dig down into the leaf litter.

These frozen peepers and wood frogs might look dead; their hearts have actually stopped beating. But the partially frozen frogs aren’t dead. Instead, they have a kind of natural anti-freeze in their bodies. Ice crystals form in their organs and body cavity, but a high concentration of glucose in the frogs’ vital organs prevents freezing. When spring approaches and its hibernaculum warms up above freezing, a frog’s frozen body will thaw, and it will come back to life.

As you go about preparing for winter, think of the frogs with their amazing adaptations for survival, safe in their winter homes, waiting for spring.

Here’s a video from YouTube about the hibernation of a wood frog. It’s pretty amazing—take a look!

This is a partial repost of an earlier post from December 2010. Most of the information from the post came from an article in Scientific American, How Do Frogs Survive the Winter? by Rick Emmer.

Tags: amphibian hibernation, amphibian life cycle, aquatic frogs hibernation, frog hibernaculum, Frog hibernation, frog life cycle, frogs ectothermic animal, spring peeper hiberation, terrestrial frogs, what do frogs do in the winter, what do frogs do the in the fall, wood frog hibernation, wood frog video
Posted in Climate change and frogs, Frog hibernation, Learn about Frogs, Life Cycle of Frogs | 1 Comment »