“Here is a question and answer (Q & A) contribution, focused on the reptile fauna in Singapore, with particular attention to the forest-specific species that live in the Central Catchment Nature Reserve. To protect our native reptiles, we have to be aware of their diversity, habitat requirements, behaviour, ecology and population status.
Q: What are reptiles?
A: Reptiles are animals with back-bones (vertebrates) and have their entire body covered with scales of different shapes, sizes and colours. The main groups of reptiles include the crocodiles, lizards, snakes and turtles. Their metabolic rate is often affected by the environmental temperature. They reproduce by laying eggs with leathery to hard shells.
Q: Why are reptiles important components of the ecosystem?
A: Many of them are carnivores, feeding on a varied diet of insects, worms, small mammals, birds, amphibians, fish and even other reptiles. Hence, they are key predators in forests and streams. Some reptiles, such as monitor lizards, play the role of scavenger and consume dead or dying animals. Terrapins which feed on fallen fruit can help to disperse the seeds of native forest plant species.
Q: How many species of reptiles are living in Singapore?
A: Singapore has more species of reptiles than the United Kingdom. At least 29 species of lizards, 50 species of snakes, and six turtles occur in Singapore. Of these, more than half live within our Central Nature Reserve. Now if you have a serious phobia of snakes, then you may wish to consider living in New Zealand, which is a snake-free country.
Q: Which species of native reptiles live only in our forests?
A: The following are representative reptilian species that have been thriving in the mature forests of MacRitchie for countless generations.
• The Earless Agamid, Aphaniotis fusca (below) climbs among the vines and branches of the cool and shady understorey, in search of bugs and beetles to feed on.
• The Green Crested Lizard, Bronchocela cristatella (below) can blend in well amongst dense forest foliage. It is also a good climber and is able to take bold leaps from the canopy.
• Kendall’s Rock Gecko, Cnemaspis kendallii (below) is often active by day and is well adapted for scrambling over the rough surfaces of rocky boulders and tree bark.
• The Lowland Dwarf Gecko, Hemiphyllodactylus typus (below) is only active at night (nocturnal) and patrols broad leaves to feed on small insects, such as ants and flies.
• The Clouded Monitor, Varanus nebulosus (below, photograph by Vilma D’Rozario) is perfectly at home in the trees, sleeping up there by night and basking in the sun in the mornings. It will not hesitate to consume a rotting carcass, yet also spends much of its time scraping the forest floor for earthworms and insects.
• The Twin-barred Tree Snake, Chrysopelea pelias (below) is highly arboreal and spends much of its life amongst the branches. Geckoes are one of its favourite prey items.
• The Red-tailed Racer, Gonyosoma oxycephalum (below) is a gorgeous green snake with a brick-red tail. This species is also arboreal and has a keen sense of smell, which will lead it to either bat roosts or bird nests in search of a warm-blooded meal.
• The Bigeye Green Whip Snake, Ahaetulla mycterizens (below) is the smaller relative of the more commonly seen Oriental Whip Snake, Ahaetulla prasina. It has relatively larger eyes and only lives in undisturbed forests, often close to streams.
• The Wagler’s Pit-Viper, Tropidolaemus wagleri (below) surely is one of the finest snakes in our forests, patiently poised and waiting for the right moment to strike at any passing prey. With special pits near their nostrils, they can detect the warmth emanating from a nearby rat or bird. They have a highly prehensile tail, which coils around branches for a secure grip.
• The Spiny Hill Terrapin, Heosemys spinosa (below, photograph by Vilma D’Rozario) is probably one of the most long-lived of our forest reptiles. However, they also grow and breed very slowly. As their diet includes fallen forest fruits, these terrapins help to disperse the seeds of local forest plants far and wide.
• The Forest Softshell Turtle, Dogania subplana (below-top) is a strict inhabitant of clean and clear forest streams. Its shell consists of cartilage, which makes it more flexible than its hard-shelled cousins. It is an amazing ambush predator – its entire body will be buried and concealed beneath the sandy substrate, with only the eyes and nostrils poking out to seek passing fish prey (below-bottom).
Q: What can happen to our forest reptiles if their habitat is disturbed or demolished?
A: First and foremost, the lives of many aquatic and amphibious species will be disrupted. With excessive siltation and decreased visibility, predators like the Forest Softshell Turtle will encounter great difficulty in locating prey. If clearing of vegetation involves the felling of trees, many arboreal species will be adversely affected. Many tree-dwelling lizards or snakes can be faithful occupants of particular roost sites or perches up in the branches of mature trees. Prolonged earthworks and excavation activity with noisy machinery will drive away many snakes, which are inherently sensitive to the slightest vibrations.
Q: What is a ‘refuge’?
A: According to the ‘Cambridge International Dictionary’, ‘refuge’ refers to a place which gives protection or shelter from danger, trouble, unhappiness, etc. The Central Catchment Nature Reserve has indeed been a refuge for such a high diversity of reptiles for the longest time. We hope that it will continue to do so indefinitely.
Dr. Leong Tzi Ming & Dr. Vilma D’Rozario
8th June 2013