WALLACE’S FLYING FROG: Rhacophorus nigropalmatus is the well known flying frog of Southeast Asia. It actually glides from the canopy or tree trunks using its relatively large webbed feet.
THE mysterious worlds of frogs opened up recently thanks to Dr Indreneil Das – an internationally respected herpetologist – who is a professor of herpetology at the Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak (Unimas).
Ironically, during a time when about a third of the approximate 7,000 known species of frogs are threatened, Das, who is leading the search for unidentified species, has identified several new ones, including the smallest, a pea-sized frog from the Microphylla family that in habitats the liquid in the pitcher plant Nepenthes ampullaria’s cups.
During the talk, Das said that one new species is identified each week. This bloom in species has several sources, including formally inaccessible places, such as mountaintops, suddenly becoming reachable; micro-species are identified; and sub-division of species due to genetic analysis.
Frogs and toads, members of the Anura order, as well as other amphibians, including temperate salamanders, which superficially resemble lizards, and legless tropical ceaecillians – often mistaken for earthworms or snakes – are facing a mass extinction on the same scale as the one that wiped out dinosaurs.
Several factors have been identified as contributing to their demise including pollution, pesticides, habitat loss, climate change, hunting, predators, pet trade but the most deadly is the chytrid fungus disease (Batrachochytrium dendrobactidis). It is fatal because the fungus coats the delicate amphibian skin blocking the pores, which are used for water and moisture transfer, thus killing the frog from dehydration and heart failure.
Frogs and toads are a diverse group filling a vast array of ecological niches ranging from streams, to pools in the forests and even in liquid-filled pitcher plant cups. Amphibians have a water phase and a land phase.
The egg masses like sago pudding are generally laid in water including ponds and streams.
The herbivorous tadpoles, which hatch from the eggs, go through metamorphosis. Gills develop into lungs, limbs develop, as does the nervous system. It is a dramatic transformation.
Most adults are carnivores eating smaller creatures, including insects and snails, however, there is one Indian species that is herbivorous. In Central and South America, where the frog populations have been decimated, mosquito populations and thus the diseases they carry are likely to increase. We are only now beginning to understand the complexities of parental care. In the past it was thought that once the eggs were laid, the young were left to fend for themselves. This is not the case. Frogs which lay their eggs on land carry water to the tadpoles and eggs to ensure that they do not dry out.
BORNEAN HORNED FROG: Megophrys nasuta is a leaf litter-like camouflage frog. It hunts by ambushing nearby prey. — Photos by Methos Phang
A South American species brings food to the young tadpoles, while another, probably extinct, female gastric-brooding frog swallowed the fertilised eggs and let them develop in her stomach. Pouched frogs have pockets of skin that can be used to carry eggs and tadpoles, while in some species care is divided between the male and female.
These creatures generally appear to be relatively defenceless as they are not particularly fast moving, nor do they have teeth or claws. Most species depend on camouflage and generally their skin exudes toxins.
Toxicity is normally advertised by bright colours, for example a red frog is probably poisonous. However, for some the warning colours are hidden. It is advised, because most frogs and toads exude toxins, to wash after handling them.
Frog song has disappeared in many places around the world; we are fortunate that frog populations still sing at morning and dusk, as well as live in the wild in Sarawak. Who knows, perhaps species are dying out before even being identified.
The plight of frogs and other amphibians is highlighted internationally on ‘Save the Frog Day’ on April 27. The Frog Race, which is organised in conjunction with this international day, by Unimas and the Sarawak Forestry Corporation (SFC), will be held at Kubah National Park, Matang.
The race is on to take digital photographs of frogs in their natural settings with prizes for teams who see the most, take the best photographs and ‘capture’ the rarest amphibian.
Teams will walk the marked trails of Kubah National Park for two hours taking digital images of the amphibians they see. These images will be downloaded and then become part of the competition. Frog safety is key and the frogs should not in any way be further endangered by this competition.
There will be lots going on if you want to take in the fresh air, but not venture out to photograph amphibians. Interesting talks on amphibians, their conservation in addition to visual and audio displays of frogs are scheduled. They are an indicator species of the health of natural ecosystems, and their demise shows just how much has gone wrong.
What can we do? Well personally I believe we must protect the frogs that continue to live by not hunting them. We must avoid purchasing exotic species of frogs. We can also reduce our use of plastic (a major pollutant), pesticides and take steps to stop contributing to climate change.
To learn more about frogs and the danger they are in go to www.savethefrogs.com. Visit the Frog Race website at www.theboreneanfrograce2013.weebly.com to learn more about this exciting event and to join it.