September 5, 2017

Kermit the Frog’s saying, “With good friends, you can’t lose,” appears to apply—rather unusually—to the marsh frog and the Anatolian water buffalo of northern Turkey. A Polish ecologist was bird watching in the Kızılırmak Delta along the Black Sea coast, one of the largest wetlands in the Middle East, when he accidentally happened upon water buffaloes covered with hitchhiking frogs. One water buffalo had 27 frogs clinging to its fur! After this chance discovery, Piotr Zduniak of Poznań‘s Adam Mickiewicz University suspected the animals were more than simple friends, and that their relationship may have biological importance. There are many symbiotic relationships in nature (sharks and pilot fish, for example), but the case of the buffalo and the frog would be the first such mutually beneficial relationship between a mammal and an amphibian. Zduniak, along with two other researchers, carefully studied the buffalo-frog connection, and they found that the phenomenon takes place only in autumn. They explained why in the June 2017 issue of the journal, Acta Herpatologica.

Marsh frogs get cozy on the back of a water buffalo in northern Turkey. Credit: © Nizamettin Yavuz, Firenze University Press

Marsh frogs are not too picky about what they eat, and the species often changes its diet according to what is available. They eat mainly insects, but they sometimes dine on fish, other amphibians, and small mammals. Like many wild beasts, water buffaloes are rife with flies. A slow-moving, marsh-wallowing water buffalo can thus provide frogs with a pleasant sort of dining cruise. And given the choice between being covered in flies or frogs, these buffaloes apparently prefer frogs. More study is needed, however, to prove the buffalo’s preference. Why, for instance, do frogs and buffaloes show this behavior nowhere else? There may be something in the Anatolian marsh water. And why in autumn? Aside from food, the cold-blooded frogs may cling to the warm-blooded buffalo for warmth as temperatures cool later in the year.

Scientists believe marsh frogs cling to water buffaloes for food and warmth. Credit: © Nizamettin Yavuz, Firenze University Press

In nature, a mutualistic relationship occurs when two parties benefit by living in close quarters with each other. For example, certain kinds of ants live in thorny plants. The plants provide food and nesting sites for ants. In return, the ants provide protection from insect pests. The case of the buffalo and the frog is definitely symbiotic, in which one animal always benefits (the frog), and the other animal (the water buffalo) probably also benefits. A similar relationship exists between the small oxpecker bird and large animals of the African plains. The oxpecker perches on such animals as water buffalo (which are a type of wild oxen), antelope, giraffes, rhinoceroses, or zebras. The bird then eats ticks and other small parasites from the animal’s skin and fur.

April 5, 2017

Scientists, never satisfied with the current number of known frogs in the world, have added two new species of toads to the ever-growing list. These new toads, native to Indonesia, have DNA so different from other toads that scientists went a step further and gave them their own genus, Sigalegalephrynus. When classifying living things, a genus (a group of related animals or plants) ranks below a family or subfamily and above a species. The discovery of a new frog genus is rare. The last one in Asia occurred in the 1800’s. The new toads live in a densely vegetated volcanic region of Batang Gadis National Park on Sumatra, one of the world’s largest islands. One species was found in a shallow cave; the other was scurrying about the nearby forests. (Remember that frogs and toads are not different animals. Toads are simply certain types of frogs.)

A toad of the new genus Sigalegalephrynus sits among the bristly hairs of a leaf. These toads resemble puppets used in funerary festivals in Sumatra, the island in western Indonesia where the toads live. Credit: © Eric N. Smith, Amphibian And Reptile Diversity Research Center/University of Texas at Arlington

Researchers spent eight months in 2013 and early 2014 taking inventory of the toads in the Sumatra Highlands. Then, for more than a year, they studied their findings and analyzed the physical and genetic characteristics of these unusual specimens. The researchers used nuclear and mitochondrial cell data to describe the toads, and the results showed that members of Sigalegalephrynus are unique among other toads of that region. The researchers’ findings were published in the March 2017 issue of the journal Herpetologica. Herpetology is the branch of zoology concerned with the study of reptiles and amphibians.

The new toads have unusual chattering mating calls unlike other frogs of their native land. Sigalegalephrynus are medium-sized toads with lanky limbs. Most are mottled dark brown and tan, but one version has green colors on its body. Because of their resemblance to wooden puppets used in local ceremonies in the region, these frogs earned the name of “puppet toads.” But their name can extend further. The wooden puppets are used during specific funerary festivals to appease the spirits of the dead. So, these newfound amphibians are sometimes called “puppet toads of the dead.”

The discovery of these puppet toads comes as scientists and conservationists feel mounting urgency to locate and classify species throughout Indonesia, where toads and many other forms of life are threatened by deforestation. About half of Indonesia’s amphibian species are not found anywhere else in the world. The future of the “puppet toads of the dead” and other Indonesian wildlife depends on saving the precious forests they call home.

March 24, 2017

If you are lucky enough to go camping along the banks of the Paraná River in the Argentine Pampas of South America, be sure to carry an ultraviolet (UV) flashlight with you. Among the leaves, vines, and creepy crawlies, you just might find glow-in-the-dark frogs! A couple of weeks ago, a team of researchers from the University of Buenos Aires and Brazil’s University of São Paulo discovered the first fluorescent frog near Santa Fe, a city in northeastern Argentina. Yes, these frogs can create their own light! This first fluorescent frog, the polka dot tree frog, is already well-known and commonly found throughout the Pampas and the nearby Amazon Basin, so it is not a new species. But scientists did not know the amphibians had fluorescent “power” until now.

The one-and-only glow-in-the-dark polka dot tree frog changes color at sunset. Credit: © Carlos Taboada, Bernardino Rivadavia Natural Sciences Museum (Buenos Aires)

The capability to absorb light at short wavelengths and re-emit it at longer wavelengths is called fluorescence. It is uncertain why some animals have this ability, but it may be used to communicate, for camouflage, or to attract a mate. Fluorescence is fairly common in the ocean, where fish, plankton, and even sea turtles can emit their own light. In the desert, scorpions also glow in the dark. But never before has anyone seen a phosphorescent amphibian. Scientists found that the 1.2-inch (3-centimeter) polka dot tree frog’s glowing ability come from a compound found in the lymph and skin glands of its translucent (see-through) body. The fluorescence does not work in complete darkness, but rather at twilight, when the frog’s skin has recently absorbed light, and its color goes from a dull pale green with speckled white, yellow, or reddish spots, to a bright green with dark spots.

A polka dot tree frog (Hypsiboas punctatus) pretends to be just like any other tree frog during the day. Credit: © Patrick K. Campbell, Shutterstock

There are thousands of frog species around the world, and they live on every continent except Antarctica. If you pay attention, you’ll notice that new frog species are discovered fairly often. Their sometimes tiny size and reclusive habits in the remotest of forests make some frogs extremely hard to find. The polka dot tree frog may be the first fluorescent frog known to science, but the ever-evolving natural world is bound to be hiding others in the darkest corners of Earth—just keep your UV light on and your eyes open!

March 9, 2017

After five years of exploration and study in the mountainous Western Ghats region of India, scientists have announced the discovery of seven new species (kinds) of frogs. Four of these new species are among the tiniest known frogs in the world, small enough to gather more than one on a 5-rupee coin (the rupee is the chief monetary unit of India). The frogs belong to the genus Nyctibatrachus with the common name of night frog—so called because of their nocturnal (active in the night) habits and dark coloring. The smallest of these newfound night frogs is less than 1/2 inch (1.2 centimeters) long!

A newly discovered and identified Robinmoore’s night frog (Nyctibatrachus robinmoorei) has plenty of leg room on the Indian 5-rupee coin. Credit: © SD Biju

Most night frogs live in forest streams, have large webbing on their feet to swim around their aquatic habitat, and emit loud calls. Some can reach up to 3 inches (7.6 centimeters) long. Finding night frogs has never been an easy task, but the habits and smaller size of the newly found frogs make them even even more elusive. The newly discovered night frogs live mainly beneath damp soil or dense, wet vegetation, not in the water like most night frogs. They are also much quieter than other night frogs, featuring an insectlike call similar to the chirp of a cricket. Plus, four out of the seven species are extremely small. It is no wonder they went undiscovered for so long! Because they live mainly out of water, these new frog species—which have proved to be surprisingly abundant in the Western Ghats—have little or no webbing on their feet.

The newly found Athirappilly night frog (Nyctibatrachus athirappillyensis) comes from areas along the Athirappilly Falls on the Chalakudy River, site of a proposed hydroelectric dam. Credit: © SD Biju

The first frogs appeared on Earth during the Jurassic Period, which lasted from about 200 million years ago to about 145 million years ago. Thousands of species of frogs have evolved (developed over time) from these early ancestors. Night frogs are found only in southern parts of the Western Ghats region of India and represent an ancient group of frogs that populated the region about 70 million to 80 million years ago. Unfortunately, one-third of the frogs in the Western Ghats region are threatened with extinction. Increased conservation efforts are needed to protect these new species as well as other night frogs from threats posed by habitat loss, pollution, and climate change.

November 10, 2016

Flash! Flash! Flash! No, it’s not photographers following around Hollywood stars. It’s a new species of frog that flashes in a different kind of way, with a showy display to ward off attackers. Dr. Simon Clulow of the University of Newcastle in New South Wales, Australia, and his team discovered this new species while surveying amphibians in a coastal sand swamp at Oyster Cove, about 6 miles (10 kilometers) from Newcastle Airport. New vertebrate discoveries are rare, but it is incredibly rare to discover a new species so close to a populated area. Newcastle is the second most populated area of New South Wales (only Sydney is larger).

Australia’s tiny new frog species, Mahony’s toadlet, shows off part of its flashy under area. The species was discovered in a relatively urban environment near Newcastle, Australia, in 2016. Credit: © University of Newcastle

The tiny Mahony’s toadlet (Uperoleia mahonyi), also known as the “flasher frog,” is named after Professor Michael Mahony, a renowned frog expert and conservationist and Dr. Clulow’s mentor and supervisor. The frog has warty glands on its back similar to toads, and it fits on the tip of an adult person’s thumb. One of the frog’s defining characteristics is its beautiful black-and-white marblelike belly. Its unique belly pattern, one not witnessed in Australia before, led Clulow to recognize the frog as a new species not previously described. One other unique characteristic is what puts this frog over the top—its flashing ability! If its natural camouflage fails to hide it from predators, the frog will flash the bright orange rust color of its groin area. This brightly colored area, which remains hidden while the frog is resting, contrasts sharply with the rest of the frog, so it delivers quite a shock to such likely attackers as birds, rats, and snakes. The flash-driven pause of the attacker often allows Mahony’s toadlet to dart away and disappear into the undergrowth of its swampy environment.

At the moment, the habitats where Mahony’s toadlets live are relatively safe and in good condition, but with encroaching housing developments, sand mining, and other human activities, Mahony’s toadlet may be gone more quickly than it was found. Researchers estimate the flasher frog population to be rather small, so conservation efforts must be made to help this new species of frog continue to thrive and flash, flash, flash.