The Bornean Rainbow Toad, scientifically known as Ansonia latidisca, is a captivating amphibian species endemic to the island of Borneo. Also referred to as the Sambas Stream Toad, this small, vibrantly colored toad holds a special place in the world of herpetology due to its elusiveness and recent rediscovery. This article delves into the fascinating aspects of the Bornean Rainbow Toad, covering its habitat, diet, unique characteristics, and the conservation challenges it faces.
Rediscovery After Decades of Mystery
The Bornean Rainbow Toad gained considerable attention when it was rediscovered in 2011, after being unseen for 87 years. The last confirmed sighting of the toad was in 1924, making its reappearance a momentous occasion for scientists and conservationists alike. The rediscovery was made by a team of researchers from Universiti Malaysia Sarawak (UNIMAS), led by Dr. Indraneil Das. Inspired by Conservation International's (CI) "Global Search for Lost Amphibians," the team located three individuals of the long-lost toad in the Gunung Penrissen mountain range, in the Malaysian state of Sarawak.
Before its rediscovery, the Bornean Rainbow Toad was only known from three specimens and a single black-and-white illustration from the 1920s. The rediscovery provided the first-ever photographs of the colorful amphibian, transforming it "from a black and white illustration to a living, colorful creature."
Habitat and Distribution
The Bornean Rainbow Toad is endemic to the island of Borneo, which is shared by Indonesia, Malaysia, and Brunei. Specifically, it inhabits tropical moist lowland forests and rivers within the region. These toads are often found at elevations between 900 and 1,700 meters, in the montane rainforests of Borneo. The species was found at night in a little-explored area of the Gunung Penrissen mountain range. The area is currently accessible due to the construction of a resort, including an 18-hole golf course.
Physical Characteristics
The Bornean Rainbow Toad is a small species, with adults ranging in size from 30 to 50 mm (1.2 to 2.0 in) in length. One of the most striking features of this toad is its vibrant coloration. They have variegated dorsal skin "splattered in bright green, purple, and red." The colorful spots on the dorsum are not flat but "pebbly" and have been compared to warts. These colors serve as excellent camouflage against the mossy tree bark of their rainforest habitat.
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In addition to their coloration, Bornean Rainbow Toads have long, spindly limbs that are well-adapted for climbing. These adaptations reflect their arboreal lifestyle, as they are often found in the high branches of trees.
Behavior and Diet
Bornean Rainbow Toads are nocturnal creatures, meaning they are most active at night. As nocturnal foragers, they primarily feed on small insects and invertebrates. They hunt at night, using their keen vision and agility to capture prey. Their diet plays a crucial role in maintaining the balance of their ecosystem, as they help control insect populations.
Reproduction
Little is known about the specific mating habits of the Bornean Rainbow Toad, but they are likely similar to other frogs and members of their genus. Males may call to attract females during the breeding season, and eggs are probably deposited in streams. The species is believed to have torrent-adapted tadpoles, which develop in fast-flowing water.
Conservation Status and Threats
The Bornean Rainbow Toad faces significant threats from habitat destruction and degradation. The IUCN Red List of Threatened Species lists Ansonia latidisca. Deforestation for palm oil plantations is a major concern, as it leads to the loss of their natural habitat and food sources. The primary threats to their survival include habitat loss due to deforestation for agriculture, particularly palm oil plantations. Logging activities not only destroy their habitat but also cause sedimentation of streams, which impacts their breeding grounds. Pollution run-off from logging and agricultural activities further degrades their habitat. Poaching for the international pet trade adds to the pressure on their population.
The habitat in which it is found it not currently under protection and is threatened by forest fragmentation, poaching, and resort development. The exact location of the rediscovery of the frog is being withheld given concerns it would become targeted for the pet trade, especially with its bright and unique coloring.
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Conservation Efforts
Effective preservation of the hilly rainforest regions in Borneo is crucial for the survival of the Bornean Rainbow Toad. Conservation measures are needed to protect it from vanishing again. One potential conservation strategy is the creation of a rainbow toad reserve.
The Search for Lost Amphibians
The rediscovery of the Bornean Rainbow Toad was part of a larger effort to find lost amphibian species around the world. In August, a group of conservation agencies launched the Search for Lost Frogs, which employed 126 researchers to scour 21 countries for 100 amphibian species, some of which have not been seen for decades. The search for 100 of the world’s ‘lost amphibians’-unseen for decades and in many cases supposed extinct-have turned up three species so far, one of which hasn’t been recorded since the Nazis were bombing London. The lost amphibian expeditions, formed by Conservation International (CI) and the IUCN Amphibian Specialist Group (ASG), have found surviving populations of the cave splayfoot salamander (Chiropterotriton Mosaueri) in Mexico, the Mount Nimba reed frog (Hyperolius Nimbae) in the Ivory Coast, and the Omaniundu reed frog (Hyperolius sankuruensis) from the Democratic Republic of Congo.
CI’s Global Search for Lost Amphibians covered five continents and 21 countries looking for 100 amphibians, many not seen for decades. The official search only found four of the lost hundred, an additional sign that many of the world’s amphibians are simply lost for good.
Amphibians have been devastated over the last few decades; highly sensitive to environmental impacts, species have been hard hit by deforestation, habitat loss, pollution, agricultural chemicals, overexploitation for food, climate change, and a devastating fungal disease, chytridiomycosis. Currently the IUCN Red List estimates that 41 percent of the world’s amphibians are threatened with extinction. Frogs, salamanders, and worm-like caecilians have been battered worldwide by habitat loss, pollution, agricultural chemicals, overexploitation, and climate change. Yet the biggest impact on amphibians appears to be a fungal disease called chytridiomycosis. Researchers say that in the past 30 years, its likely 120 amphibians have been lost forever. Experts say that in the past 3 decades it is likely at least 120 amphibians have gone extinct. In a few cases captive populations in zoos have become a species’ last stand.
The Bornean Frog Race
The International Bornean Frog Race celebrates frogs. Artists, scientists, school children and photographers gather in the Park headquarters to paint, learn, and document a day dedicated to frogs. The day transitioned into an evening of amphibian-related talks, and I had an opportunity to present to the gathered crowd on photography and storytelling as tools for conservation. It is always a pleasure to speak to an engaged audience, and this crowd was as passionate as they come.
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As darkness fell, the 100-plus photographers that had signed up for the race began clicking and flashing in anticipation as they checked memory cards, snapped on lenses, and shaped homemade diffusers. After listening intently to the rules of the race, they scurried into the forest, where they had two hours to find and photograph frogs. As the race drew to a close they gathered like moths around a line of students illuminated behind laptops to download their images for judging. The best photo, rarest species, most species, and best photo taken with a phone were selected and projected onto a big screen following a live auction of frog paraphernalia, and the photographers responsible for each awarded generous cash prizes.
It was an inspiring and fun evening, and a creative way to connect people with amphibians. The concept was the brainchild of a student of Dr. Das from Universiti Malaysia Sarawak named Pui Yong Min and, as impressive as his vision for the race has been, Pui also has another claim to fame. He was the first person to set eyes on the Borneo Rainbow Toad in 87 years.