Having had to cut short the previous walk in August due to rain, we were delighted to have clear weather for our latest walk in September, once again at the MacRitchie Treetop Walk! We also welcomed two members of the Little Green Men, Sarah and Frances, to join us on our walk; if you’re interested in making a difference for the environment however you can, try contacting them!
Even before all our participants had arrived, our dedicated spotter Wei Yang found the first herp of the day: a beautiful Oriental Whip Snake (Ahaetulla prasina)! One of the most commonly sighted snakes in Singapore, it ranges widely into parks and gardens to feed on small lizards like geckoes and skinks. With their brilliant green colour and sinuous bodies, they can be easily mistaken for vines or climbing plant tendrils. Mildly venomous, this snake is harmless to humans though it can bite when provoked. As Sankar explained, they are viviparous, meaning they give birth to live young! The word “viper” in fact is derived from “vivipary”, as vipers are amongst the snakes that have this trait.
As we trekked deeper into the forest, several Many-lined Sun Skinks were seen basking in patches of sunlight that managed to penetrate to the understory. We also found many weird and wonderful arthropods, such as the caterpillar above! The fact that it was bristling with spines that may also contain venom would have been difficult to swallow for many a bird. 
We were fortunate to have Sean Yap, a member of the Entomological Network of Singapore (ENSING) as well as HSS, to help us identify these strange critters found swarming about on a wooden railing. Apparently these are barklice (Order Psocoptera); harmless insects that feed on algae, fungi, and dead plant tissue that grow on trees, they help keep them clean of detritus!
We also stumbled across this cool-looking Flat-backed Millipede (Platyrhacus lineatus) with plates whose edges jutted out from the main body. This makes it difficult for predators to attack its more vulnerable underbelly.
Herps aren’t the only animals that struggle with an image issue. Cockroaches are often hated for being pests that feed on our trash and spread disease. But our native cockroaches play an important role in the forest by feeding on dead organic matter and speeding up the recycling of nutrients! And some of them can be pretty adorable too, like the Pill Cockroach (Perisphaerus sp.) shown above! Who knew that cute cockroaches were a thing!
Having already trained their eyes with those small little invertebrates, one sharp-eyed participant spotted this Red-crowned Barbet (Psilopogon rafflesii) on a dead tree trunk! Restricted only to our mature forests, it may have been digging for insects or perhaps building a nest.
At last, more herps! The Black-bearded Flying Dragon (Draco melanopogon) on the left was showing off its patagium, the flap of skin that allows it to glide between trees! If you look closely, you can see the rib bones that the lizard swings outwards to open up its wingsuit! This individual may have been displaying to another flying dragon to warn it to keep to away from its territory.
The lizard on the right is the elusive Yellow Striped Tree Skink (Lipinia vittigera), courtesy of our veteran elf-eyed spotter, Ing Sind. Small and nimble, it usually hides amongst the roots of epiphytes (plants that grow on other plants, usually trees, such as orchids) or in tree crevices, emerging to feed on small insects. Like many lizards, it is able to drop off its tail when threatened, and this one was in the midst of regenerating it. The tails of lizards often contain important stores of fat and contribute to maintaining its balance, so losing it, while not life-threatening, can be a major blow; so leave lizards alone, lest they inadvertently lose their head and lose their tail!
While on the Treetop Walk itself, we spotted another species of gliding lizard, the Sumatran Flying Dragon (Draco sumatranus)! This one, probably a male, was flashing its yellow dewlap to warn off other males and perhaps show off to nearby females.
We were lucky to meet not one, put two vipers on this walk! Both were male or possibly juvenile Wagler’s Pit Vipers (Tropidolaemus wagleri), coiled around young tree seedlings along the trail. These are ambush predators, lying in wait for prey such as small mammals and birds to wander past before striking with lightning fast speed and their forward-swinging fangs. With heat-sensitive pits on their snouts and blood-destroying haemotoxin, these are formidable foes to their enemies, and should always be treated with caution. As the vipers were located extremely close to the trail, well within striking distance of unwary hikers, we gently lifted them deeper into the undergrowth with a long stick; this was for their own safety as well as the safety of others.
On the way back to the Ranger Station, we came across this blooming Tiger Orchid (Gramatophyllum speciosum)! The largest orchid in the world, it went extinct in the wild in Singapore over a century ago before being reintroduced by NParks in various parts of the island. Each individual plant only blooms every few years, with a massive stalk of up to 80 sweet-smelling flowers. We were fortunate to have come across this specimen while it was flowering.
No Herp Walk is complete without a sighting of at least one monitor lizard, and true enough we found this large Clouded Monitor (Varanus nebulosus) basking in the sun! Unlike their bigger cousins the Malayan Water Monitors, Clouded Monitors are restricted to forests and feed mainly on insects and other arthropods they find by digging amongst leaf litter. The widespread presence of these lizards are a testament to how herps can coexist and thrive peacefully in our city. In fact, just the night before our walk, one of its cousins gained international fame by sprinting across the F1 race track during the qualifying rounds! And although that Water Monitor avoided being turned into a pancake, roadkills of these magnificent creatures are sadly all too common. If you’re a driver, slow down, especially near vegetated areas; it saves lives, both human and herp alike!
As we always like to say, don’t Beware of Snakes (and herps); be Aware of them! Spread what you’ve learned to your family and friends too, so that we can continue sharing this little green dot with our herpy friends for generations to come!
Herpetological Society of Singapore 