Thursday, September 27, 2012

Limpets of Singapore

"Limpet" is a common name for various groups of marine snails with flattened conical shells, and these different snails may not even be closely related. The term "true limpet" is used to describe members of the clade Patellogastropoda. It can get rather confusing trying to differentiate the various species of true limpets and false limpets, and hence I decided to create this page to list the snails with flattened conical shells that I had photographed in Singapore. I hope this will make it easier for readers of my blog to identify to the species or genus. You may want to take a look at my diagram on the parts of a snail's shell if you are not familiar with the names of the parts, so as to better understand the terms used below.

Rayed Wheel Limpet (Cellana radiata)
Rayed Wheel Limpet (Cellana radiata) - From the family Nacellidae, the Rayed Wheel Limpet is a true limpet. It has a mother-of-pearl iridescence on the interior of its shell, which can be seen sometimes on the exterior surface too on well-eroded shells. It also has folds on the mantle edges acting as secondary gill leaflets, and a long radula (tongue-like structure for feeding) several times longer than the shell. It is usually found on rocky shores, and like other limpets, it does not move much during low tide to avoid dehydration, and also, the rocks will be baking hot under the sun. During high tide, it will move around, grazing on algae on the rock surface. It can grow to about 4cm long.

Sweet Limpet (Patelloida saccharina)
Sweet Limpet (Patelloida saccharina) - From the family Lottiidae, the Sweet Limpet is also a true limpet. Instead of breathing through secondary gills, it has feather-like gills, and the interior of its shell is porcellaneous. The shell is bilaterally symmetrical - very obvious with the prominent ridges (or ribs) on the shell exterior. Like the nacellids, they clamp tightly to the rocks during low tide, sealing the shell edges with the rock surface, protecting them from desiccation. This adaptation, together with their flattened conical shell also allows them to survive the strong waves pounding against the rock. It can reach length of about 2cm.

Javan Siphon Shell (Siphonaria javanica)
Javan Siphon Shell (Siphonaria javanica) - From the family Siphonariidae, the Javan Siphon Shell is not a true limpet, and hence the members of this family are often also called False Limpets. Unlike the true limpets that breathe with gills, siphonariids breathe with simple lungs. In addition, siphonariids are hermaphrodites, meaning each animal possesses both male and female reproductive systems, while true limpets have separate sexes. It is possible to differentiate some of the species by looking at the shells - the Sweet Limpet's shells are bilaterally symmetrical, if you look at the patterns and sculptures, but not the Javan Siphon Shell. It is about 1cm across.

Guam Siphon Shell (Siphonaria guamensis)
Guam Siphon Shell (Siphonaria guamensis) - Also from the family Siphonariidae, the Guam Siphon Shell has thinner and less protruding ribs, many of which are not continuous (with breaks in between). This is usually smaller, less than 1cm long.

Flattened Siphon Shell (Siphonaria atra)
Flattened Siphon Shell (Siphonaria atra) - Another member of the family Siphonariidae, the Flattened Siphon Shell is flatter and the ribs have the same colour as the background, and hence are less prominent. This species can reach length of about 2cm.

Singapore Keyhole Limpet (Diodora singaporensis)
Singapore Keyhole Limpet (Diodora singaporensis) - From the family Fissurellidae, keyhole limpets have a hole at the top of the shell, and they are not true limpets as well. Instead of exposing their shells to the sun clinging to the rocks, they are usually found under rocks or in shady areas during low tide. Their flattened shells allows them to easily creep under rocks and into cracks and crevices to seek food and also to avoid the hot sun. The Singapore Keyhole Limpet is usually of a light brown, with darker bands radiating from the keyhole. The shell lacks the serrated or uneven edges found in many other keyhole limpets, and forms a nice oval shape at the base. It can grow to about 2cm long.

Chinese Shield Limpet (Scutus sinensis)
Chinese Shield Limpet (Scutus sinensis) - Also from the family Fissurellidae, shield limpets are usually found under rocks as well, usually with their mantle extending out of the shell and covering part of the shell. The Chinese Shield Limpet's mantle is brownish with darker blotches. It can grow to about 4cm long.

Nail Shield Limpet (Scutus unguis)
Nail Shield Limpet (Scutus unguis) - Another member of the family Fissurellidae, the Nail Shield Limpet has a black mantle which can cover the entire shell, hence it is sometimes mistaken for a slug. It can reach a length of about 4cm.

Walsh's Slipper Limpets (Siphopatella walshi)
Walsh's Slipper Limpets (Siphopatella walshi) - From the family Calyptraeidae, the Walsh's Slipper Limpet appears like one side of a clam shell. It is a snail though, with a single white shell. Instead of attaching to rocks like the other limpets above, Calyptraeids attach themselves to shells occupied by hermit crabs or to the undersides of horseshoe crabs. They are filter feeders, and hence living with the hermit crabs means opportunities of food particles sent to the water column as the hermit crabs feed. The bigger females can grow to about 3cm acaross.

Cup-and-Saucer Limpet (Calyptraea extinctorium)
Cup-and-Saucer Limpet (Calyptraea extinctorium) - Also from the family Calyptraeidae, the Cup-and-Saucer Limpet attach itself to shells occupied by hermit crabs as well. It has a conical shell though, unlike the more flattened shells of the slipper limpets. The ones in Singapore grow to about 1.5-2cm long.

Cup-and-Saucer Limpet (Calyptraea extinctorium)
The above photo features a Cup-and-Saucer Limpet lifting up its shell, revealing its soft body.

  • Gladys Archerd Shell Collection at Washington State University Tri-Cities Natural History Museum. 2008. Retrieved September 26, 2012, from
  • ETI BioInformatics. 2012. Marine species identification portal. Retrieved Oct 3, 2012, from
  • Oliver, A. P. H. 2012. Philip's guide to seashells of the world. Philip's, London. 320 pp.
  • Tan, K. S. & L. M. Chou, 2000. A guide to common seashells of Singapore. Singapore Science Centre, Singapore. 168 pp.
  • Tan, S. K. & H. P. M. Woo, 2010. A preliminary checklist of the molluscs of Singapore. Raffles Museum of Biodiversity Research, National University of Singapore, Singapore. 78 pp. Uploaded 02 June 2010.
  • Tan, S. K. & R. K. H. Yeo, 2010. The intertidal molluscs of Pulau Semakau: preliminary results of “Project Semakau”. Nature in Singapore, 3: 287–296.
  • World Register of Marine Species. 2012.  Retrieved Oct 3, 2012, from

Friday, September 21, 2012

Mammals (Phylum Chordata: Class Mammalia) of Singapore

Mammals are my favourite group of animals, and thanks to a few really nice people, I had the opportunity to tag along mammal surveys or educational trips, and got to see and photograph many of our mammals. I longed to blog about our native mammals, but as most of these trips are research trips, I could not publish the photos online. And then one day, it suddenly dawned on me that the Zoo actually has many of our native animals, so why not I blog with photos taken in the zoo? Together with photos taken in Malaysia and other photos taken in Singapore but on non-research trips, I now finally have enough photos to put up a blog post! Shouldn't be difficult for you to tell which are the zoo photos, but these are definitely animals that you can find in in the wild in Singapore...

Mammals (phylum Chordata, subphylum Vertebrata, superclass Tetrapoda, class Mammalia) are air-breathing vertebrates (animals with a backbone and a hollow tube of nervous tissue called a spinal cord) characterised by the possession of hair on their body; the ability to produce milk in females to feed their young; the ability to generate body heat and maintain it within a narrow range, i.e. they are endothermic; and the possession of three middle ear bones.

Most mammals give birth to live young, though  a few species of extant mammals still produce water-tight egg. Other vertebrates which produce water-tight eggs include the birds and many of the reptiles, and they are usually referred to as "amniotes". They are descended from four-limbed ancestors (hence the superclass Tetrepoda which means "four legs").

Here are some of the native mammals of Singapore.

Order Pholidota

Sunda Pangolin (Manis javanica)
Okay, I know this is a really lousy photo, but unfortunately, I did not managed to get any better shots of the Sunda Pangolin (Manis javanica) at the Night Safari, and I have to blog about this since this is my favourite native animal of Singapore! I am still hoping very hard that I will see a live pangolin during my own trips instead of during a survey trip, so that I can share the photo online. From the family Manidae, this animal has a robust body covered with scales (which are actually modified hair), short legs, strong claws and a prehensile tail. Pangolins feed on ants and termites by ripping their nests apart with their fore-claws, and lapping them up with their long and sticky tongues. They are largely nocturnal, and sleep in burrows underground in the day, though some have been observed to climb up and sleep on trees. They can swim well. When threatened, they usually curl up into a ball. The young pangolin follows its mother and rides on her tail.

Order Carnivora

Leopard Cat (Prionailurus bengalensis)
The Leopard Cat (Prionailurus bengalensis) is the only native species from the Cat Family (family Felidae) that still can be found in Singapore. It got its common name from its spots, resembling a leopard's spots. It is about the size of a domestic cat and feed on small animals, such as rodents, amphibians and birds. While they move around both in the day and at night, they mostly hunt when it's dark. They live alone except during the breeding season.

Common Palm Civet (Paradoxurus hermaphroditus)
The Common Palm Civet (Paradoxurus hermaphroditus), locally called the Musang, is a from the family Viverridae. It is NOT a cat, so please don't call it a civet "cat" - civet is good enough. Common Palm civets can be found both in the forest and also in residential areas with plenty of trees. In Singapore, they are known to live in the roof spaces of houses, but they mostly nest in hollow trees. They are largely nocturnal, though the urban civets in Singapore can sometimes be seen playing in the day as well. They feed mostly on fruits (including those of palms, and hence the common name) and sometimes insects. For defence, they have anal scent glands which emit a nauseating secretion when threatened. Some people actually keep it for the production of a very expensive coffee - Kopi Luwak, which is prepared using partially digested coffee cherries eaten by the animal, harvested from its feces. This civet is also called the Toddy Cat, as it appears to like drinking the palm sap collected in vessels placed in palms that is used for making toddy (palm wine) or palm sugar.

Malayan Civet (Viverra tangalunga)
The Malayan Civet (Viverra tangalunga) is only determined to be a native species recently. Like the Common Palm Civet, they are nocturnal and feed on both fruits and small animals. In other countries in the region, they can be found in a variety of habitats, ranging from forest to outskirts of villages. In Singapore, they have only been seen in one of the nature reserves.

Smooth Otter (Lutrogale perspicillata)

The Smooth Otter (Lutrogale perspicillata) is the bigger of the two species of otters (family Mustelidae) found in Singapore, reaching a length of more than one metre. It feeds mainly on fish, and sometimes molluscs and crustaceans. The digits are fully webbed, allowing them to swim efficiently. Smooth Otters are diurnal, and usually seen in pairs or small families in our mangrove forests, in tidal rivers and reservoirs near the sea.

Oriental Small-clawed Otter (Aonyx cinerea)
The Oriental Small-clawed Otter (Aonyx cinerea) can be active both day and night, and unlike the Smooth Otter, the digits are only partially webbed. They are also smaller, and feeds mainly on molluscs and crustaceans - their last two upper teeth are larger for crushing the shells. They sometime feed on other smaller animals such as fishes, amphibians and snakes. They are often seen in family groups.

Order Artiodactyla

Lesser Mouse Deer (Tragulus kanchil)
The Lesser Mouse Deer (Tragulus kanchil) is a small, deer-like animal from the family Tragulidae found in our forests. Despite the name, it is not a deer, but is more closely related to pigs. It does not have horns or antlers, but instead has elongated canine teeth which are especially prominent in the males. It is active periodically both day and night, and feed on fallen fruits, shoots and fungi.

Greater Mouse Deer (Tragulus napu)
The Greater Mouse Deer (Tragulus napu) was thought to be extinct in Singapore until it was rediscovered in recent years on Pulau Ubin. The sub-species found in Singapore is more brownish than orange, unlike the one shown above. It is mainly nocturnal, but is known to be active during the day sometimes. It feeds on fallen fruits, leaf shoots and other vegetation.

Sambar (Rusa unicolor)
The Sambar (Rusa unicolor) is a large deer from the true deer family Cervidae, and can get longer than 2m. The native deer is believed to be extinct in Singapore, and the current population in our forests is thought to be unintentionally introduced (zoo escapees). It feeds on grasses, herbs, fruits and leaves of shrubs and small trees. They are mainly nocturnal, and hence despite their big sizes, they are not often seen. They are good swimmers. Only the males have antlers.

Wild Boar (Sus scrofa)
The Wild Boar (Sus scrofa), also known as Wild Pig, is the wild ancestor of the domestic pig. Interestingly, the term "boar" is often used to describe only the males for other pig species from the family Suidae, but for the Wild Boar, it applies to the whole species, i.e. both sexes. According to the "Wild Animals of Singapore", they were believed to be locally extinct, and the current population is descended from individuals which swam over from Malaysia. They are active both day and night, feeding on fallen fruits and digging for roots and worms. As they lack a natural predator in Singapore (with the tiger and other big cats being extinct), the authorities have decided to cull them to control the population. While any ecologist will agree with that, it was unfortunate, however, that some people claimed that the Wild Boars had caused the population of mouse deer at Lower Pierce to decrease, stating that they used to see mouse deer 7 or 8 times out of 10 trips, but they hardly see them in recent years. This is, of course, rubbish, since I have been seeing mouse deer on almost all my trips to Lower Pierce for the past one year, and in fact, saw 4 of them during one trip.

Order Primates

Long-tailed Macaque (Macaca fascicularis)
Singapore has two native species of monkeys, and the Long-tailed Macaque (Macaca fascicularis) is one of them. It got its common name from its long tail, which can be longer than its body, distinguishing it from the other macaques in the region. Long-tailed Macaques, from the family Cercopithecidae, can be found in a wide variety of habitats, from inland forest to mangroves. They are opportunistic omnivores, eating a variety of animals and plants, including crabs if they live in the mangroves (and hence they are sometimes also called Crab-eating Macaques). They live in groups, and are a lot more daring compared to the locally much rarer Banded Leaf Monkeys (Presbytis femoralis), which are very shy. Unfortunately, some people fed the Long-tailed Macaques with human food, and as a result, many of them started associating human with food. There were cases of monkeys snatching food from human, or even attacking them if they were carrying food. For these monkeys to go back to their old ways of finding their own food in the forest and stop harassing human, people will have to stop feeding them and stop carrying their food out in the open when they visit nature areas. Eventually, the monkeys will stop associating human with food.

Sunda Slow Loris (Nycticebus coucang)
The Sunda Slow Loris (Nycticebus coucang), from the family Lorisidae, is a small nocturnal and arboreal primate. Apologies that you can't see the face in the picture above, as it was sleeping since it's day time. It is believed that its slow lifestyle could be due to the energy costs of detoxifying the poisonous plants in their diet. They feed mostly on plant sap, nectar and fruits, though some have been observed to feed on insects and snails. The slow loris is among the few venomous mammals in the world. They can produce a toxin in glands on the insides of their elbows, which they lick and mix with their saliva.

Order Rodentia

Malayan Porcupine (Hystrix brachyura)
The Malayan Porcupine (Hystrix brachyura) is a species of rodent from the family Hystricidae. The hairs on its back are modified into sharp spines to deter predators. It is mainly nocturnal, and stays in deep burrows in the day. They feed on fallen fruits, roots, and sometimes insects and carrion. Once thought to be extinct in Singapore, it has been rediscovered on the northern islands and also on mainland Singapore.

Rats (family Muridae)
Several species of rats (family Muridae) can be found in Singapore. While the urban species are often associated with diseases and garbage, the forest species are generally rather clean, feeding on insects and fruits. They are mostly nocturnal, but I have personally seen many rats in the day as well, including the forest species. Many live in burrows, while others may live in holes in buildings and trees.

Plantain Squirrel (Callosciurus notatus)
The Plantain Squirrel (Callosciurus notatus) is a squirrel (family Sciuridae) commonly seen in our forests and parks. The genus name "Callosciurus" means "beautiful squirrel", as most of the squirrels from this genus have pretty colours/patterns. Plantain Squirrels are diurnal, and feed mostly on fruits and nuts, though they sometimes eat insects and eggs as well. They usually nest on tree by building a spherical arrangement of twigs and leaves, lined with fur.

Slender Squirrel (Sundasciurus tenuis)
The Slender Squirrel (Sundasciurus tenuis) is smaller, and feeds on soft tree bark, fruits and insects. It is not as widespread as the Plantain Squirrel, but can still be easily seen in the Central Nature Reserves and the Singapore Botanic Gardens.

Horsfield's Flying Squirrel (Iomys horsfieldi)
Apart from the diurnal squirrels, we have nocturnal ones too! The Horsfield's Flying Squirrel (Iomys horsfieldi), despite the name, can glide (not fly) from tree to tree. It has a large flap of skin on each side of its body between the limbs, which it will stretch and open up so that it can glide like a kite for long distances. It feeds on fruits and insects. Another flying squirrel found in our forests is the Red-cheeked Flying Squirrel (Hylopetes spadiceus).

Order Scandentia

Common Treeshrew (Tupaia glis)
The Common Treeshrew (Tupaia glis) is sometimes mistaken to be a rat, shrew or squirrel due to its pointed nose and bushy tail, but it is in fact from a different order (Scandentia) and family (Tupaiidae) altogether. Despite the name, treeshrews are commonly seen on the forest floor in the day, hunting for small insects and lizards. They also feed on fruits and seeds. They live in permanent pairs and are very fateful to their mates. Researchers sometimes use treeshrews as animal models for human diseases due to their close relationship to primates and well-developed senses of sight and hearing.

Order Dermoptera

Malayan Colugo (Galeopterus variegatus)
The Malayan Colugo (Galeopterus variegatus) is a gliding mammal that can be found in our forests. From the family Cynocephalidae, it has a thin membrane stretching all the way from its neck to the fore limbs, across the fingers, along its body to the hind limbs and eventually to the tail, allowing it to glide for long distances. Colugos are nocturnal and feed largely on leaves. In the day, they cling on to the sides of tree trunks or branches. The baby colugo usually follows the mother, clinging on to its underside. Studies have shown that male colugos in Singapore are mostly brownish, while the females are greyish in colour.

Order Chiroptera

Fruit Bat (Cynopterus sp.)
The only mammals that can fly are the bats (order Chiroptera), and unfortunately I only have the photo of a Fruit Bat (Cynopterus sp.) here. Fruit bats feed on fruits and nectar, and contrary to the saying "as blind as a bat", it actually has good eyesight. Most fruit bats lack echolocation and move around using their eyesight and smell - it the first place you cannot locate a fruit (which does move) just by echolocation. Bats that feed on insects, however, will use echolocation to locate their prey. You may have noticed that all these mammals which glide or fly are nocturnal, possibly to avoid competition and predation from the better flyers - the birds.

Order Cetacea

Indo-Pacific hump-backed dolphin (Sousa chinensis)
We have marine mammals too, such as dolphins, porpoises and dugongs (yes, they are not fishes!). The Indo-Pacific Hump-backed Dolphin (Sousa chinensis) and Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) are regularly seen in our waters. Occasionally, the Irrawaddy Dolphin (Orcaella brevirostris) and the Finless Porpoise (Neophocaena phocaenoides) are also seen. Being mammals, they do not have gills and hence have to breathe air. As such, they have to surface regularly to breathe. Apart from good eyesight, they generally are able to echolocate, i.e. they can emit calls to the surrounding and listen to the echoes to determine to some extend what is around them, such as their prey or non-prey.

Order Sirenia

Dugong (Dugong dugon) feeding trail
And while the Dugong (Dugong dugon) is only occasionally seen in our waters, their feeding trails can be seen among the seagrass meadows on both our northern and southern shores! Being rather big eaters, they create little bulldozer trails as they munch up the root systems (or rhizomes) and leaves.

Protecting our Native Mammals

Rather sadly, many of our mammals are affected by the lost of habitat. Our forest is getting smaller and smaller, despite our green space getting bigger with the parks replacing the forests. Many of our terrestrial mammals require good forest to survive. And also, our forests are becoming more fragmented and disconnected with other forest patches. This resulted in animals not being able to exchange genes and hence inbreeding, which may cause genetic illnesses and animals dying out.

The introduction of alien species has also affected our native mammals - an example can be seen with the introduction of the Variable Squirrel (Callosciurus finlaysonii) in Bidadari and Woodleigh, which is competing with our native Plantain Squirrels.

There are also poachers around, and I have personally seen poachers setting up traps to trap monkeys and squirrels, and they keep their traps only after they saw me calling the authorities using my mobile phone. Irresponsible forest users, such as mountain bikers who created new trails in the forest and cut down trees ad shrubs, have also cause much stress to the more shy animals.

Hence, in my opinion, it is important that the public are educated on how vulnerable our native mammals are, such that we can better protect them. The authorities probably also need to plan future developments more carefully, and perhaps to maintain strips of forest as green connectors instead of destroying everything - if they can have park connectors, why not have forest connectors as well? Joggers will then be able to enjoy the shade as they jog, and animals can also use these connecting greenery to travel around and exchange genes.

  • Baker, N. & K. Lim, (Vertebrate Study Group, Nature Society Singapore), 2008. Wild animals of Singapore. Draco Publishing and Distribution Pte. Ltd.
  • Baker, N. (2012). Ecology Asia. Retrieved September 20, 2012, from
  • Francis, C.M., 2008. A field guide to the mammals of South-east Asia. New Holland.

Tuesday, September 18, 2012

Berlayer Creek & Bukit Chermin Boardwalk

Officially opened on 2 January 2012, the Berlayer Creek and Bukit Chermin Boardwalk is part of the 2.1km-long Labrador Nature and Coastal Walk. The boardwalk runs for about 960m along the 5.6-hectare Berlayer (or Berlayar) Creek, home to one of the few natural riverine mangrove forests left in Singapore, before it winds towards Keppel Island.

Berlayer Creek is actually part of what used to be a small tidal river in the southern part of Singapore. Urban development work has claimed most part of the original river system, but a small portion near the estuary was spared. The area was named after a historic rock formation, Batu Berlayer, which means “Sail Rock” in Malay, that stood at its estuary. This rock formation, together with another similar-looking one on the opposite shore of Tanjong Rimau on Sentosa, once formed some kind of "gateway" for boats. Due to these two sharp rock formations, the gateway was called 龙牙门 in Chinese, meaning Dragon Teeth's Gate.

The National Parks Board has done up a very nice online guide on this nature spot, and hence I will focus more on some of the things to note, and the ecological aspects along this boardwalk instead.

Dos & Don'ts
  1. Stay on the boardwalk, or you may end up trampling the flora and fauna.
  2. Bring water and some light snacks, as you can only buy drinks at the end of the boardwalk at the cafe at Keppel Marina or from the vending machines at Labrador Park.
  3. Keep your volume down, or you may disturb the very animals you want to see, and they may hide away from you.
  4. Take nothing but photos, leave nothing but foot prints. Bring your litter out with you, and never take anything from the forest. Poaching has resulted in severe reduction in the population of much wildlife in many places.
  5. You may want to bring insect repellent just in case, though I personally have not encounter many mosquitoes there.
  6. Please bring a cap/hat in case of sunny weather, and raincoat/poncho in case of wet weather. I would also recommend bringing a few plastic bags to keep your electronic products in case it rains.
  7. Bring a camera along, but remember to have a plastic bag to keep it dry in case it rains.

What to Expect at the Boardwalk

The entrance to the boardwalk is located near the Labrador MRT Station. Do check out the various cultivated native plants around the MRT station before you enter the boardwalk beyond the pavilion.

Once you enter the boardwalk, you will be greeted by a beautiful riverine mangrove forest. Riverine mangrove forests are those that occur along tidal rivers. As a result, the river has more freshwater during low tide, fed by its tributaries upstream, but gets inundated with sea water during high tide. In a typical riverine mangrove forest, the trees are usually taller and healthier, as the area will be enriched by nutrients from its tributaries. However, due to development, the main source of freshwater for Berlayer Creek is now is left with a small drain, and hence the amount of nutrients received by the forest is also affected.

Like other mangrove forests, the plants found in a riverine mangrove forest still has to adapt to the various challenging conditions - the soft and unstable mud, the lack of oxygen in the soil, and the salt (which has a drying effect). As a result, most mangrove plants spread their roots widely for more stability; develop aerial roots to take in oxygen from the atmosphere; and either block most of the salt at the root level, or excrete salt through glands on the leaves.

Berlayer Creek is home to the largest population of the Bakau Pasir (Rhizophora stylosa) on mainland Singapore. This is a nationally vulnerable mangrove tree with hard and heavy wood traditionally used for making charcoal. It relies on its roots to exclude salt from entering the plant through a process called ultrafiltration. The thin and long structures seen hanging from the trees are the seedlings, not fruits - the seed develops shoots and roots while still attached to the tree. Mature seedlings are dispersed by water and have a greenish collar. The seedling floats horizontally for a few weeks, during which the root (lower part) will absorb water and become heavier, eventually causing the seedling to tip and float vertically. As the tide goes down, the vertically-oriented seedling will sink into the mud or other suitable substrates.

The Api-api Ludat (Avicennia officinalis), a common magrove tree, is also found here. "Api-api" means "fire-fire" or "firefly" in Malay, as some Avicennia species are noted to attract fireflies. Research indicated that roots of Avicennia species also exclude some salt from entering the plant. It also has glands to excrete salt that is not excluded at the roots.

After the short loop among the trees, the boardwalk continues along side with the forest. Several interesting coastal and mangrove plants can be seen along the trail. In the photo above, you can see a Malayan Banyan (Ficus microcarpa), which is a fig tree, with the long dangling roots. As fig trees produce figs very regularly, they are able to provide regular food supplies for all kinds of animals such as birds and monkeys, unlike other forest trees that fruit perhaps once a year or even once every few years. In fact, such large fig trees play a critical role in providing food and shelter, and studies suggest the number of such fig trees limit the number of animals found in a forest.

The authorities had planted many native plants along the boardwalk, making this a nice trail to learn some of our native coastal plant. I will just highlight a few of the planted ones here:

Many young Gedabu (Sonneratia ovata) have been planted here. This critically endangered mangrove bears round persimmon-like fruits which are edible. It uses ultrafiltration to block the salt at the roots, just like the Bakau Pasir.

The Limau Hantu (Suregada multiflora) is another nationally critically endangered tree planted here.The fruit resembles small lime, hence the Malay name "Limau Hantu" which means "ghost lime". Studies shown that extracts from this plant has antibacterial and insecticidal properties. More recent studies showed that it has some anti-HIV and anti-cancer properties as well.

Yet another critically endangered tree planted here is the Sea Teak (Podocarpus polystachyus). The timber from this tree is hard and durable, and is used in some places to make furniture and house interior. It is also planted for ornamental purposes.

Of course, looking at planted trees can never be as interesting as finding the wild ones. Apart from the Bakau Pasir and Api-api mentioned at the beginning of this post, there are a few other mangrove and coastal plants here like the Bakau Putih (Bruguiera cylindrica), Buta-buta (Excoecaria agallocha), Nipah Palm (Nypa fruticans), Mangrove Derris (Derris trifoliata) and Sea Hibiscus (Talipariti tiliaceum). But it would be a lot more interesting to try to spot the ones that are really uncommon at this particular mangrove forest.

The Chengam (Scyphiphora hydrophyllacea) is rather commonly seen in our other mangroves, but somehow only a few can be found at Berlayer Creek. The small fruits are cylindrical and green, and they are dispersed by water.

The Teruntum Merah (Lumnitzera littorea) is an endangered mangrove tree. The authorities had planted many young ones along the boardwalk, but there is one huge and tall wild one among the wild trees. It has pretty red flowers, blooming in clusters. The small and somewhat corky fruits are buoyant and dispersed by water. The wood is hard and extremely durable, and is used for the building of bridges, wharves, cart axles, flooring and sleepers. It has a rose-like scent, making it popular as a cabinet timber.

You will sharp eyes to spot the Kalak Kambing (Finlaysonia obovata), a critically endangered climber. The fruits appear like a pair of horns, and hence the common name "kalak kambing", which means goat's horn. The young leaves of this plant are apparently eaten by some as a vegetable.

The hardest to spot, however, is a tall and mature Berembang (Sonneratia caseolaris), a nationally critically endangered mangrove tree closely related to the Gedabu mentioned earlier. I only know of less than 10 wild trees left on mainland Singapore, the others are: three (possibly a young fourth one to be verified) at Woodlands; one at Sungei Buloh; and one at Kranji. Several other wild ones can still be found on Pulau Ubin and Pulau Tekong though. Like the other Sonneratia species, the flowers usually bloom at night and are pollinated by nectar-feeding bats and moths at night, and birds in the morning.

Apart from the plants, the usual mangrove animals can be seen here too.

The mudskippers are among the easiest to spot. The above is a Giant Mudskipper (Periophthalmodon schlosseri). This is the biggest species of mudskipper in Singapore. This fish can survive out of water by holding water in its mouth and gill chamber. It is rather aggressive and hunts small animals such as crabs and worms for food.

The Collared Kingfisher (Todiramphus chloris) can also be seen, if not heard, here. Apart from small fishes, it feeds on small crabs, shrimps and insects too. Apart from kingfishers, many other birds, such as green pigeons, orioles, bulbuls, sunbirds and even a few migratory waders, can be seen here.

If you are lucky, you may chance upon the Plantain Squirrels (Callosciurus notatus). They feed mostly on fruits and leaves, though they may also eat insects and bird eggs.

Many butterflies and moths can be seen here, and hence it's no surprise you may see caterpillars here too. The above is an Atlas Moth (Attacus atlas) caterpillar. The Atlas moth is the biggest moth in the world in terms of total wing surface area, and its wingspan is also one of the widest, up to 30cm.

The boardwalk will bring you towards the see and eventually to the Bukit Chermin section of the boardwalk. While you are here, remember to look down to see if there are any schools of fishes around. If the tide is low, you can even see little crabs!

Do also check out the rare Johor Fig (Ficus kerkhovenii) growing on the cliff as you head towards the marina.

And here's the Marina at Keppel Bay!

If you look down, you will notice that there are lots of soft corals and other organisms growing on the sides of the floating pontoon!

Here's a closer look - can you see a clam, soft corals, seaweeds, and a pair of tunicates (the thing below with a pair of holes each)?

You can even find colourful cave corals!

If you still have energy after the walk, you may want to consider going to Labrador Nature Reserve, which is just nearby, where more nature awaits!