About three dozen related species of flying lizards — including Draco lizards — are found in Borneo, peninsular Malaysia, some of the islands in Indonesia, India and Australia. They generally glide from tree trunk to tree trunk like a flying squirrel and have the ability to loop around the tree for a better position.
There are both nocturnal and diurnal varieties. They forage for ants and termites. Many species are quite territorial. If a rival arrives the resident lizard will quickly swoop down next it, launching into off aggressive displays — flicking out the triangular skin under the lizards’s chins — until the intrude leaves. In the mating season, males stake out territories and display their prominent dewlaps to attract females and scare off rival males. Sometimes males chase each other through the air and from tree to tree.
The most common flying lizard is eight-inch-long “draco volans”. When at rest its greenish or greyish skin blend in well with the bark or leaves of trees. Some have bright orange patches on their flying membrane that only become exposed when they fly. The markings may scare or confuse predators. Males have a throat appendage or “fan” that is orange. Females have a fan that is blue.
Flying Lizards in Flight
Flying lizards can glide for up to 100 feet and flit about easily from branch to branch. They create a gliding surface with skin stretched between the elongated false ribs on each side of their bodies. At rest these ribs are folded up against the body like wings. When they leap the ribs pulls forward, causing the false ribs to extend and the skin around them to open up like an umbrella. The gliding is used primarily as a way to get from places to place and quickly escape predators. It isn’t used so much to pursue prey. For that the crawl around like regular lizards although sometimes they will pounce on an insect that exposes itself within range of a quick flight. .
Describing how the Draco flying lizard flies, David Attenborough wrote, " "It's ribs are hugely elongated. When the animals is sitting quietly on a branch, they lie close to its body, parallel to its spine on which they are hinged. When it jumps, its abdominal muscles contract, drawing the ribs forward so that they fan out and expose a wide flap of brightly colored kin on either side of the body."
Amphibians in Southeast Asia
Jodi Rowley, herpetologist with the Australian Museum in Sydney, told mongabay.com: “Southeast Asian amphibians are poorly known—new species are continuously being discovered and for the species that we do know of, we don’t know enough about many of them to know if they're threatened with extinction or not. In fact, 36 percent are so poorly known that they are listed as "Data Deficient" according to the global IUCN Red List, which is 11 percent higher than the global average for amphibians. Because we don’t yet know the true diversity or conservation status of Southeast Asian amphibians, they've tended to slip under the global conservation radar. However, the fact we don’t know enough about what is going on is alarming in itself—there’s actually very good reasons to be concerned about Southeast Asian amphibians. [Source: Jeremy Hance, mongabay.com, February 6, 2012 ::::]
“Even as amphibians face unprecedented challenges—habitat loss, pollution, overharvesting, climate change, and a lethal disease called chytridiomycosis that has pushed a number of species to extinction—new amphibians are still being uncovered at surprising rates. One of the major hotspots for finding new amphibians is the dwindling tropical forests of Southeast Asia. The best place to discover new amphibian species in Southeast Asia are high-altitude montane forests. Rowley says there is a number of reasons for this: "Montane forests are areas of high amphibian diversity. They’re also areas of high endemism—over time, frogs on mountains often become 'trapped,' unable to cross valleys to reach the next mountain, and become different species—those adapted to the unusually cool, wet conditions found at the top of mountains. The inaccessibility of montane areas (rugged terrain in remote areas) has also afforded the forest in these areas some protection from habitat destruction." ::::
“A large proportion of the amphibians in Southeast Asia remain undiscovered. Exactly how many, I’m not sure. Looking at how many new species of amphibian are described from Southeast Asia every year, there’s still a lot to discover. I have a few favorite places, and each of these places are special for different reasons. Because it's the place that I have been back to the most, I do love the Langbian Plateau in southern Vietnam. The amphibians of the area are diverse, and many are known only from the Plateau's misty mountains. I’ve also worked with protected areas staff in the area for many years, and so got to know them well. ::::
“With the paucity of knowledge on Southeast Asia's amphibians, scientists know less about their overall conservation status as compared to amphibians in Africa and Latin America. However, given that Conservation International has dubbed Southeast Asia's tropical forests the most imperiled in the world, it's likely that many of the region's amphibians are struggling to survive.” ::::
Vampire and Bird Frogs of Southeast Asia
Jodi Rowley told mongabay.com:“So far, my colleagues and I have discovered and described ten species of frog. The actual discovery—spotting the frog and realizing that it’s from a species not known to science—is fantastic, but brief. Most of the work actually occurs once we are back in the lab—comparing the body size and shape, and colors and patterns on the frog to other species known from the region, and examining molecular data and advertisement call recordings. [Source: Jeremy Hance, mongabay.com, February 6, 2012 ::::]
“I have a particular fondness for the vampire flying frog (Rhacophorus vampyrus). It’s also been the species that has received the most attention. Its unusual name is for a good reason though—the tadpoles of the species are truly bizarre. With two, curved, black "fangs" protruding from their mouth in place of the usual tadpole mouthparts, I think it deserves the name and the attention! There’s no doubt a fascinating reason for these teeth—and we’re working on discovering that. The frog itself is also quite a beautiful species—brick red, black and white, with large, golden eyes. ::::
“Quang’s tree frog is unique in its tiny size, turquoise skin and black and yellow patterns, but it’s most unusual because of its call. Instead of calling repeatedly "croak, croak, croak..." as most frogs tend to do, males of this species make an unpredictable and variable array of clicks and whistles. No two of calls are the same—making it a little more like a bird than a frog in terms of calls. “ ::::
The Bornean horned frog is brown and black and very well camouflaged, blending in perfectly with the leaf litter where it hangs out. They are very hard to find. They don’t move now matter how close one approaches. In terms of prey, it simply waits for insects and other small creatures to pass its way.
Threatened Amphibians in Southeast Asia
Jodi Rowley told mongabay.com: “Southeast Asian amphibians are facing some serious threats—including the highest deforestation rates on the planet and overharvesting (for food, pets or traditional medicine). They’re also now known to be infected by the pathogen responsible for amphibian declines and extirpations globally (Batrachochytrium dendrobatidis). So by all accounts, they are facing a very real extinction crisis. However, because we know so little about the amphibians of the region, and haven’t been monitoring populations all over the region, amphibian population declines and extinctions may be going unnoticed. ::::
“By far the greatest threat to amphibians in Southeast Asia is habitat loss. While some amphibians are able to persist in human-modified habitats such as pastures, rice-paddies and even cities, most simply can’t tolerate much habitat modification at all. For example, many amphibians are almost completely arboreal, even breeding in water-filled pools in trees. Without a healthy forest with lots of "holey" trees, there’s no way they can survive. ::::
“Amphibians are harvested for food (either to feed people or animals), for use as traditional medicine, and for the domestic and international pet trade. Harvesting amphibians for food is on a much greater scale than the other two, and there’s evidence that over-harvesting for human consumption may be threatening long-lived and large-bodied frogs—they seem to be absent in areas where they were once abundant. The harvesting and trade of Southeast Asian salamanders is also very worrying. Salamanders in the region are used as traditional medicine and are in high demand in the international pet trade. Because very high prices are commanded for each individual (up to several hundred U.S. dollars), particularly if they belong to a rare species, there’s incentive to catch every last one. ::::
On the the fungal disease, chytridiomycosis, which has decimated amphibian populations in the Americas, Rowley said : We know that the pathogen responsible for the disease, Batrachochytrium dendrobatidis, is present and infecting amphibians in Southeast Asia, but we don’t know if it’s actually causing disease (eg. making the frogs sick) or affecting the populations of amphibians in the region. So far, there's no evidence that it is, but a lot more research is needed to determine if this is the case. If it is causing population declines as it has in other parts of the world, then the disease could quickly become the greatest threat facing amphibians in Southeast Asia—potentially wiping out the amphibian species that have been spared from habitat loss. We're currently hoping that Southeast Asian amphibians are somehow resistant.
According to an article published in the journal Conservation Biology last October, the wild harvesting of amphibians and reptiles is driven chiefly by consumer demand, largely from developed nations but increasingly, from Asian countries. At the losing end of the bargain are South-East Asian countries, the source of these wildlife. We’ve already encountered the “Asian Turtle Crisis” which saw drastic declines in tortoises and freshwater turtles in the region. Now, it looks like the trade in Asian snakes is fast gearing up to become another crisis.
Captive Frogs May Be Spreading Diseases to Wild Frogs in Southeast Asia
Jeremy Hance of mongabay.com wrote: “Scientists have documented a series of links between exotic frogs for trade and diseases in wild frogs in Southeast Asia, including the first documented case of the chytrid fungus—a virulent and lethal disease—in Singapore. According to researchers writing in a new study in EcoHealth, frogs imported into Southeast Asia as pets, food, or traditional medicine are very likely spreading diseases to wild populations. [Source: Jeremy Hance, mongabay.com, March 07, 2013]
Collecting samples of some 2,300 wild and captive frogs across four countries (Laos, Cambodia, Vietnam, and Singapore), researchers found that disease was widespread. Most worryingly, the researchers found chytrid fungus on two wild frogs and eleven captive frogs in Sinapore. In fact, four out of seven pet stores visited on the island nations sold frogs already infected with chytrid. They believe the American bullfrog is the primarily culprit."Since the American bullfrog is able to tolerate this pathogen, it may act as a carrier for spreading chytrid to the region when it is imported through commercial trade," explains lead author Martin Gilbert with the Wildlife Conservation Society (WCS).
Chytrid fungus has spread rapidly around the world, decimating even remote and protected frog populations. It is believed to be responsible, at least in part, for a number of extinctions worldwide. Fortunately the team didn't detect chytrid fungus in Laos or Vietnam, but did find one imported frog—to be sold as food—that was carrying the disease. Another worrisome disease, ranavirus, was not discovered during testing. However, the researchers also report that amphibians in Vietnamese frog farms were rife with skin lesions. Every frog tested—497 individuals—at 23 different facilities sported some type of skin disease from inflammation to missing digits.
"In light of the fact that this emerging infectious disease is now known to be spread by commercial trade, it is in everyone’s best interest to eliminate it from the trade in live animals before both the native amphibian populations of Southeast Asia are affected and before it completely decimates the commercial trade and people are unable to make a living," said co-author David Bickford with the NUS Faculty of Science, adding, "This is not just about the frogs."
Pea-Sized Frog Found in Borneo
In April 2010, Associated Press reported: “One of the world's tiniest frogs — barely larger than a pea — has been found living in and around carnivorous plants in Borneo, one of the scientists who made the accidental discovery said. Indraneil Das, a scientist at University Malaysia Sarawak, and another scientist from Germany were researching frogs in Malaysia's Sarawak state on Borneo island when they chanced upon the tiny species on a mountain road in the Kubah National Park in 2006. "For biologists, this is a curiosity," Das told Associated Press. [Source: Associated Press, August 26, 2010]
Adult males of the amphibians range in size between 10.6mm and 12.8mm, said Das. The frogs were named Microhyla nepenthicola after the pitcher plant species where they live. A Malaysian museum had listed the species but misidentified it as a juvenile of another frog species, he said. The tubular plants are carnivorous, killing insects such as ants, but do not harm the frogs. Tadpoles grow in the liquid inside the plants. The findings were published (pdf) by Das and Alexander Haas of the Biozentrum Grindel und Zoologisches Museum of Hamburg, Germany in the journal Zootaxa last week.
Because the frogs were so small, Das and his colleague only found them by tracking their singing of "harsh rasping notes" at dusk. They caught them by making them jump on a white cloth near the pitcher plants. The discovery should encourage efforts to protect the biological diversity in Borneo's rainforests. Das said the tiniest known frog — at 9.8mm — found was in Cuba. A 8.5-millimeter frog species found in southern Papua new Guinea was named not only the world’s small frog, but the world’s smallest vertabrate, in 2012.
Image Sources: Wikimedia Commons
Text Sources: National Geographic, Natural History magazine, Smithsonian magazine, Wikipedia, New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, Top Secret Animal Attack Files website, The New Yorker, Time, Newsweek, Reuters, AP, AFP, The Economist, BBC, and various books and other publications.
Last updated May 2014