...so we should all play our part to rescue them in this Year of the Frog
Leong Tzi Ming, Straits Times 5 Jan 08;
In our human-centred world, we often ask ourselves: 'What can we get from nature that will benefit our society?' For a change, I believe we should instead ask what we can do for nature.
ACCORDING to the Chinese zodiac, we will usher in the Year of the Rat very soon. But I would like to think of 2008 as the Year of the Frog.
The frog will, of course, not be replacing the rat during Chinese New Year celebrations - but it has been singled out.
Designating 2008 as the Year of the Frog has been an initiative by the newly formed international group, Amphibian Ark (AArk), a partnership between the Amphibian Specialist Group (ASG), Conservation Breeding Specialist Group (CBSG) and World Association of Zoos and Aquaria (Waza).
The primary objectives of this international programme include promoting public awareness of amphibian population declines and attempting captive-breeding of selected frog species which are on the brink of extinction.
Frogs are the main members of the amphibian family - the cold-blooded, smooth-skinned creatures whose young hatch with gills and later develop lungs.
Never before has the world seen such a concerted effort to pool its expertise, time and resources to give our frog friends a helping hand.
Never before has the frog, often considered an unimportant 'lower vertebrate', been put on a pedestal to be showcased as a flagship species for conservation.
This sudden leap into the limelight has happened for a reason.
In the last three decades, over 100 species of frogs have crossed that thin red line and gone extinct.
And the results of the Global Amphibian Assessment (GAA) have revealed that about one-third of the world's close to 6,000 amphibian species are threatened.
It has now become apparent that the most likely causes of amphibian declines can be traced to a combination of culprits, including climate change and a recently discovered fungus.
But so what if a species of frog becomes extinct?
First, when any kind of indigenous frog disappears entirely, an important slice of the eco-system pie is removed, leaving a gaping ecological void which may not be filled by any other animal, thus tilting the natural balance that has been in place for eons.
Secondly, when a frog is declared extinct from any country, its name is 'struck off the register' and the amphibian fauna becomes poorer, contributing to a drop in the nation's biodiversity and an irreversible loss of a natural heritage.
Finally, another kind of loss that always accompanies a frog's extinction is its vast potential as a source of bioactive or pharmaceutical products.
Numerous tests have already been conducted using the skin secretions of a wide spectrum of frog species from around the world, with promising prospects for medical applications.
Despite having a relatively thin skin, the frog possesses special glands that are capable of creating a potent concoction of complex chemical compounds.
These include alkaloids with anaesthetic or mosquito-repellent properties, peptides with antibiotic or blood anti-coagulant properties, enzymes (ribonucleases) with anti-tumour properties, and even a hormone (thyrotropin-releasing hormone) which is also found in the hypothalamus of the human brain.
Yet another important discovery from the frog's skin is a form of sticky natural glue which has been successfully tested in the repair of torn cartilage.
From a physiological perspective, frogs that periodically hibernate in winter - such as the wood frog (Rana sylvatica) - have been found to possess their own natural anti-freeze, which keeps them alive beneath cold ice.
This offers much potential in the fields of cryopreservation and long-term storage or transplant of human organs.
Frogs, as well as salamanders, have another 'magic trick' up their sleeves. After a sustained injury resulting in the loss of arms or legs, some species have the amazing ability to regenerate an entire lost limb, complete with fingers or toes.
Scientists studying the genetics of limb regeneration have discovered a key growth factor, which has been manufactured synthetically. This may bring hope to amputees some day.
In our human-centred world, we often ask ourselves: 'What can we get from nature that will benefit our society?'
For a change, I believe we should instead ask what we can do for nature.
The humble amphibians of Planet Earth have been around far longer than we have, and they have every right to continue their existence here.
Since frogs cannot speak for themselves, I am very glad to have been a small voice for some of my favourite friends.
Let's get our hands wet and do something to rescue them from the great flood of decimation.
The writer, a zoologist specialising in amphibians and reptiles, is based at the Raffles Museum of Biodiversity Research at the National University of Singapore. He has discovered a new species of frog in Malaysia and two species previously unrecorded in Singapore.
Hopping into the spotlight
Straits Times 5 Jan 08;
There are 25 species of frogs and toads in Singapore but most people will be familiar with just one or two, particularly the bellowing call of the Banded Bullfrog (Kaloula pulchra) after a downpour as it searches for a mate. Zoologist Leong Tzi Ming, with the Raffles Museum of Biodiversity Research, takes a look at some of the other species found here and in the region.
DISCOVERED HERE FIRST
THE Malesian Frog (Limnonectes malesianus) was first described as a new species in 1984, based on specimens found in the Bukit Timah forest in Singapore.
This nocturnal forest species may venture into clearings at night.
One distinguishing feature is the W-shaped skin fold on its back. Another unique feature of this frog is a dark blotch on the tympanum - the external eardrum of frogs.
It is one of three species of amphibians that place Singapore on the map for taxonomic significance.
The frog can also be found in West Malaysia, Sumatra and Borneo.
A 'DWARF' DISCOVERY
DISCOVERED in Singapore only in 1997, the small size and soft calls of this tiny Bornean Narrow Mouth Frog (Microhyla borneensis) might have helped it to remain undetected in our forests for such a long time.
It is distinguishable from other frogs by the dark brown cross bands on its legs.
More sensitive than its relatives - the Dark Sided Narrow Mouth Frog and Painted Chorus Narrow Mouth Frog which can survive in degraded habitats and open grassland - this species needs forest cover to thrive.
POND DWELLERS
THE classic frog depicted sitting on a lily pad, this native to Singapore resides in prime pond property, such as the Botanic Gardens.
The grinning Common Greenback (Rana erythraea) is often spotted in lotus ponds and is easily identified by the pair of white bands running along the sides of its body.
Quite easy to inspect up close, it generally sits still when approached. It may also be encountered clinging to shrubs, in puddles of water or by small streams.
Its range extends across most of South-east Asia.
EYE OF THE BEHOLDER
THE Horned Frog (Megophrys nasuta) would win top awards in any local 'beauty pageant'' for amphibians for best camouflage, sharpest nose or most elongated snout, and longest eyelashes - really extensions of the skin above the eyes.
Like most frogs and toads, they are ambush predators - lying in wait in disguise in the litter of the forest floor.
They move only during rainy weather to streams for the mating season, giving out a single metallic loud honk as a call to potential partners.
Their tadpoles have mouths which are positioned upwards more like a fish, allowing them to filter feed from the water surface. This is unlike most species, which have lips that face downwards to eat off the bottom of streams.
Found only in forests, its habitats are under threat. Between 1980 and 2004, 122 species of amphibians went extinct. The World Conservation Union says a third of the world's known amphibians are threatened.
THE ODD COUPLE
IN NATURE, unusual pairings occasionally occur. For example, a cheeky Copper-cheeked Frog mating with a Common Tree Frog (Polypedates leucomystax).
Also called the Four-lined Tree Frog, the Common Tree Frog has four rows of brown markings on its back. These markings can change colour to blend in with its surroundings.
It lives near fresh water - pond edges, drains and small puddles, where it hides in low vegetation nearby. Its tadpoles have a silvery white dot at the tip of their snouts.
TOXIC TOAD
WHEN alarmed or disturbed, noxious secretions from the paratoid glands of this Cane Toad (Bufo marinus) can be poisonous to any potential predator.
This species certainly tops the list as the single most widespread and invasive amphibian, wreaking havoc in countries such as Australia.
While experts in the country despair because more money and study have been devoted to the pest than any native species, a great deal can be learned from this much maligned amphibian.
It may be top on the 'Wanted Dead'' list but it's the perfect example of good intentions gone wrong when a new species is introduced into a country.
The Green Truth
POEM BY LEONG TZI MING
Straits Times 5 Jan 08;
From the time I detect darkness descend on my pond
My senses awaken and begin to respond
You may guess that I am a creature who is active by night
That's right! I hop most happily when there is less light
When I'm hungry, I look out for worms, bugs or flies
With my long, sticky tongue, they're easily caught by surprise
My skin is green and I like keeping it wet
Because when it's moist, more oxygen I'll get
You'll know by now that I'm really a Frog
Singing my songs from the top of a log
But now I must tell you the latest news I've heard
It's weird - many friends of mine have disappeared
I'm so afraid for myself and all the family
What if we should vanish for all eternity?
I sense the climate changing, our weather's been getting hot
If I finally go extinct, I hope you'll 'froget' me not!
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