Category Archives: Frogs and the Rainforest

08/25/12

Frogs Are Blue!

Most people think frogs are green, right? And it’s true, most frogs are a greenish, brownish, yellowish color, the better to hide from predators among grass and other vegetation.

But frogs can be many different colors, even bright crayon colors like sky blue.

This three-centimeter-long blue tree frog in a tree in Chofu, western Tokyo. Courtesy of Toba Aquarium, Japan.

Why would a frog species evolve such a bright vivid color that would make it stand out? In most cases the frog, such as the colorful dart frogs, are giving a strong warning to predators: Don’t eat me! I’m poisonous! Either through instinct or through learning the hard way, predators will avoid them. These brightly colored frogs contain poisons that can kill or paralyze an animal that comes into contact with it.

The frog’s skin is not actually blue. The color comes from layers of chromotophores, or pigment-containing and light-reflecting cells between the dermis and epidermis (inner and outer skin layers). A blend of the three types of chromatophores creates the color, or in some cases, even transparency:

melanophores: contain pigments that appear black or brown from melanin

xanthophores: contain yellow colored pigments

iridophores: contain reflective or iridescent pigments

So although most of the time, frogs are green, sometimes Frogs Are Blue!

06/11/12

Remarkable Frog Dads of Papua New Guinea

This is an updated repost of a Father’s Day post from 2009.

Most animal dads aren’t too involved with their offspring (human dads, excepted of course). But two species of frogs, Liophryne schlaginhaufeni and Sphenophryne cornuta, in the microhylid frog family are devoted dads, and in fact, carry their their brood of up to 25 froglets piggyback style through the rain forest of Papua New Guinea. The frogs were discovered by evolutionary biologist David Bickford.

While most frogs start their lives as tadpoles, these frogs undergo “direct development.” They bypass the tadpole stage and go straight from larvae to miniature versions of adults while still inside the egg. This is an adaptation that allows the frog to reproduce in regions without bodies of water nearby.

After the mother frog lays the eggs, she hops off while Dad watches over the clutch, warding off predators, and keeping the eggs moist for about a month.

copyright David Bickford

copyright David Bickford

After the froglets hatch from the eggs, they hop on Dad’s back. He carries them by night through the leaf litter in the rain forest. The froglets have a free ride until they grow up a bit and can live independently (hmmm…sounds familiar).

This is an updated repost of a Father’s Day post from 2009.

02/28/12

Leap Day the Frog Way

We’re happy to feature this guest post by Meghan Bartels from the Panama Amphibian Rescue and Conservation Project in celebration of leaping frogs. Don’t miss the wonderful song below by Alex Culbreth.

The real purpose of leap day may be to keep the calendar aligned with the seasons, but here at the Panama Amphibian Conservation and Rescue Project, we’d like to believe the day is designed to honor our favorite leapers. To celebrate, we’ve put together some fun facts about frog leaping.

Frog Leaping courtesy Brian Gratwicke

Frog Leaping courtesy Brian Gratwicke & Panama Amphibian Rescue and Conservation Project

  • Not all frogs can leap, or even hop. The desert rain frog (Breviceps macrops) has legs that are too short to hop. Instead, it walks.
  • Male frogs of the genus Pipa are known to defend their territory by jumping at and then wrestling other males.
  • The New Guinea bush frog (Asterophrys turpicola) takes jump attacks one step further: before it jumps at a strange frog, it inflates itself and shows off its blue tongue.
  • Stumpffia tridactyla are normally slow-moving critters, but when they’re startled they can abruptly jump up to 8 inches. That doesn’t sound very far, but these little guys are less than half an inch long!
  • The Fuji tree frog (Platymantis vitiensis) may be the leaping stuntman of the frog world. Each time it leaps, it twists in the air—sometimes even 180 degrees—to throw predators off its trail.
  • The Larut torrent frog (Amolops larutensis) gets its name from a nifty leaping trick: it can jump into a fast-moving stream and back to its usual perch, the underside of a rock, without being affected by the current.
  • Similarly, the parachuting red-eyed leaf frog (Agalychnis saltator) gets its name because it speeds to mating opportunities by jumping from trees with finger-and toe-webbing spread wide.
  • The record for longest jump by an American bullfrog (Rana catesbeiana) recorded in a scientific paper is a little over 4 feet. But scientists who went to the Calaveras County Fair, which Mark Twain’s short story made famous for frog jumping, found that more than half the competitors bested that record—and one jumped more than 7 feet in one leap!
  • The Guinness Book of World Records doesn’t include any frogs for their leaping ability. But it does track human performance in frog jumping (jumping while holding one’s toes). There are records listed for the longest frog jump and the fastest frog jumping over 10 and 100 meters.

 

In honor of leap day celebrations being coordinated globally by Amphibian Ark, the Panama Amphibian Rescue and Conservation Project made this video for a frog song written by Alex Culbreth.

02/17/12

Listening to Frog Songs to Understand Climate Change

At Frogs Are Green, we’ve always been interested in the interconnections between frogs and the Earth. How is climate change affecting amphibian populations? Are we listening to what frogs are telling us about the health of our planet?

Recently, we read an intriguing article in the Deccan Herald (India), about how a team of scientists in India are literally listening to frogs to understand the effect of climate change on amphibian populations.

Three scientists, K.S. Seshadri with T. Ganesh, and S. Devy, were doing research 100 feet above the ground in the canopy of the evergreen forest in the Kalakad Mundanthurai Tiger Reserve. While getting drenched with rain, they heard a cacophony of frog songs. Intrigued by the songs that the rains triggered, they initiated a program to study frog calls to both monitor populations and to study the affect of climate change on frogs.

Volunteer examines the monkey-proof enclosure for equipment to record frog calls. Photo credit: K. S. Seshadri

Amphibian Meterologists

Frogs can tell us a lot about the weather. Their skin is extremely thin and sensitive; they respond to even small changes in atmospheric moisture and temperature. The scientists reasoned that an analysis of sound recordings, combined with readings from climate data loggers, could help improve our understanding of the impact of climate change.

Climate change seems to underlie many of the threats facing frogs worldwide. By monitoring the frog calls, an activity calendar for each of the indicator species can be made. This long-term monitoring will be invaluable in understanding the greater impact of climate change and also might help to save frog species.

Work station studying frog calls, high up in the forest canopy. Photo credit K. S. Seshadri

As the Deccan Herald put it: “Will the croak alarm finally wake us from our ignorant slumber? The answer lies in the future.”

For more information:

“What Frogs Tell Us About the Planet,” Decclan Herald, India

“Frog song and climate science,” Ashoka Trust for Research in Ecology and the Environment

01/13/12

World's Smallest Frog Discovered

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

07/19/11

Rare Rainbow Toad Rediscovered after 80 Years

Conservation International has announced the rediscovery in Malaysian Borneo of a vanished amphibian: the long-legged Borneo rainbow toad. Below is one of the first photographs ever of this long-legged brightly colored toad.

Photo © Indraneil Das, courtesy Conservation International

Inspired by Conservation International’s (CI) Global Search for Lost Amphibians, scientists with support from Universiti Malaysia Sarawak found three individuals of the missing toad species, up a tree during a night time search after months of scouring remote forests.

The Sambas Stream Toad, or Bornean Rainbow Toad (Ansonia latidisca) was last seen in 1924. Prior to the rediscovery,  the mysterious and long-legged toad was known only by illustrations. The rare toad was listed by Conservation International as one of the World’s 10 Most Wanted Lost Frogs, in a global campaign to seek out amphibians that have not been seen in a decade or longer.

Dr. Indraneil Das of Universiti Malaysia Sarawak (UNIMAS) and his team searched at night along the high rugged ridges of the Gunung Penrissen range of Western Sarawak. They did not find the elusive toad after searching for several months, but the team didn’t give up. Dr. Das eventually changed his team’s strategy to include higher elevations and they resumed the search. Pui Yong Min, one of Dr Das’s graduate students, found a small toad up a tree.  When he realized it was the long-lost toad, Dr. Das expressed relief at the discovery:

Thrilling discoveries like this beautiful toad, and the critical importance of amphibians to healthy ecosystems, are what fuel us to keep searching for lost species. They remind us that nature still holds precious secrets that we are still uncovering, which is why targeted protection and conservation is so important. Amphibians are indicators of environmental health, with direct implications for human health. Their benefits to people should not be underestimated.

Amphibian specialist Dr. Robin Moore of Conservation International, who launched the Global Search for Lost Amphibians to raise awareness of the serious plight of the world’s declining amphibian populations, also expressed disbelief when Das shared the good news. As he said, “It is good to know that nature can surprise us when we are close to giving up hope, especially amidst our planet’s escalating extinction crisis. “

The Global Search for Lost Amphibians, launched by Conservation International (CI) and the IUCN Amphibian Specialist Group (ASG), with support from Global Wildlife Conservation (GWC), sought to document the survival status and whereabouts of threatened species of amphibians which they had hoped were holding on in a few remote places.

The search  took place between August and December 2010 in 21 countries, on five continents, and involved 126 researchers. It represented a pioneering effort to coordinate and track such a large number of “lost” amphibians. The goal was to establish whether populations have survived increasing pressures such as habitat loss, climate change, and disease, and to help scientists better understand what is behind the amphibian crisis.

After 80 years, the rainbow toad is most definitely ready for his/her close up:

Photo © Indraneil Das, courtesy Conservation International

Read more about Conservation International’s Search for Lost Frogs.