Singapore Freshwater Crab (Johora singaporensis) @ Festival of Biodiversity, Nex, Serangoon Central, Serangoon

The Singapore Freshwater Crab is an endemic species – it’s found only in Singapore and nowhere else in the world! Sadly, this little crab, which lives in flowing streams in the forests, is now considered locally Critically Endangered, with small populations still surviving in Bukit Timah Nature Reserve, as well as within small forest patches in Bukit Batok and Bukit Gombak. Conservation of this species and population recovery will require continued protection of the few forest streams it relies on for survival and the surrounding forests, combined with efforts to breed them in captivity.

Drop by the Freshwater Crab Working Group’s booth at the Festival of Biodiversity to learn more about the 6 species of freshwater crabs found in Singapore’s forests.

Changeable Lizard (Calotes versicolor) (L) and Green Crested Lizard (Bronchocela cristatella) ® @ Singapore Botanic Gardens

What’s the connection between the Changeable Lizard and the Green Crested Lizard? Final couple of hours to drop by the Festival of Biodiversity to learn more about Singapore’s flora and fauna!

It was a long, tiring first day, but the Festival of Biodiversity continues on Sunday! Find out why the young Spiny Hill Terrapin (Heosemys spinosa) has such a bizarre-looking shell, and more weird and wonderful stories about Singapore‚Äôs natural heritage. We’ll be at the Eco Lake Lawn from 9am to 7pm. See you there!

Twin-barred Tree Snake (Chrysopelea pelias) @ VivoCity

Final few hours to find out more about these and other Singapore wildlife at the Festival of Biodiversity, happening at VivoCity this weekend!

Three species of mudskippers found in Singapore.

The eleven or so species of mudskippers found in Singapore are commonly seen in mangroves and mudflats, as well as in various other coastal habitats. Some smaller species have colonised rocky seawalls and breakwaters along our beaches and coastal lagoons, while others are found in the lower reaches of concrete drains and canals.

These highly specialised fishes flourish in environments where few other conventional fishes can, thanks to various adaptations that enable them to breathe out of water. Many species have special pouches in their gill chambers, enabling them to trap oxygenated water and air bubbles. In this manner, the gills are still able to function while the mudskipper is out of the water. So just like how a scuba diver brings an air tank down into the water, these are fishes that bring water tanks up onto land!

Some mudskippers are also able to gulp air and directly absorb atmospheric oxygen through the lining of the back of the mouth and throat, or even through moist skin.

Not all mudskippers are the same; some are more aquatic and prefer shallow mangrove creeks and pools or mudflats, leaving the water only to escape adverse environmental conditions and search for new bodies of water. Others are more amphibious, preferring the water’s edge and spending most of their time on land. Mudskipper species also differ in their diets, with some feeding mostly on algae, and others being predators of invertebrates such as worms and crustaceans.

Yellow-spotted Mudskipper (Periophthalmus walailakae) (Upper Left): This medium-sized species (up to 12 cm) found in mangrove forests is a carnivore, lunging at small crustaceans and insects.

Blue-spotted Mudskipper (Boleophthalmus boddarti) (Lower Left): This medium-sized (up to 13 cm) species can be abundant along river banks and creeks, and on mudflats on the fringes of mangrove forests. A herbivore, it feeds by wiping its face along the surface of the mud, scraping up benthic algae growing on the mud.

Giant Mudskipper (Periophthalmodon schlosseri) (Right): The largest of the mudskippers (up to 30 cm), this species inhabits mudflats, clearings in mangrove forests and edges, as well as the banks of tidal creeks and other open areas. It is often seen in or near the circular pool that it builds at the entrance of its burrow, which has a low rim of mud to trap some water even at low tide. Its size enables this predator to feed on small crabs and even other mudskippers.

These were some of the many specimens featured at the recently concluded Festival of Biodiversity 2014, which was held at VivoCity last weekend.

Assorted insects found in Singapore, representing several major groups:

  • Butterflies & Moths (Lepidoptera)
  • Beetles (Coleoptera)
  • Bees, Wasps & Ants (Hymenoptera)
  • Flies (Diptera)
  • Dragonflies & Damselflies (Odonata)
  • Earwigs (Dermaptera)
  • Cockroaches & Termites (Blattodea)
  • Mantises (Mantodea)
  • Stick & Leaf Insects (Phasmatodea)
  • Grasshoppers, Crickets & Katydids (Orthoptera)
  • True Bugs (Hemiptera)

Insects are among the most diverse groups of animals, with more than a million species described (and counting), representing more than half of all known organisms! Despite their small size, the sheer number of insects and the countless niches they occupy mean that they actually play critical roles in various ecosystems. Butterflies and dragonflies are colourful and often highly visible, whereas many other groups are poorly studied in the tropics. Singapore is home to an extremely rich and diverse insect fauna that occupies all sorts of habitats, and we are still discovering new species of insects all the time.

These were some of the many specimens featured at the recently concluded Festival of Biodiversity 2014, which was held at VivoCity last weekend.

Just so happened that yesterday (16th July) was World Snake Day, so here’s a selection of snake species found in Singapore:

Top Row (L-R)

Reticulated Python (Malayopython reticulatus):
This is the world’s longest snake, capable of growing to 9 metres in length, although most individuals never attain such sizes. Larger snakes supposedly exist, but these reports are usually wild exaggerations or otherwise difficult to verify. This is one of the most common snakes encountered in Singapore, due to its ability to survive in urban environments. Reticulated Pythons can be found in all sorts of habitats, from forests and scrubland, to neighbourhood parks, monsoon canals, and urban sewers. A row of pits in the scales that line the upper jaw enables the python to sense heat, allowing it to track warm-blooded prey and strike accurately in the darkness. Pythons have long, sharp teeth which curve backwards, making it difficult for a prey animal to break free, which makes up for the serpent’s lack of venom. Pythons kill their prey using constriction, coiling around it until the victim is incapable of breathing and asphyxiates. Rats are a favoured prey, which is why pythons do so well in urban Singapore, and in the past, pythons were infamous as poultry thieves. The larger the python, the larger the prey it can consume; adult pythons are fully capable of taking down cats, dogs, and monkeys, while truly large (and greedy!) pythons elsewhere are known to swallow large mammals such as goats and pigs. Large pythons can be dangerous – humans are typically too large to be seen as prey, but a python that is provoked often defends itself by biting and coiling around an aggressor, and may inadvertently kill the person that it perceives to be attacking it. However, such incidents are very rare; even large Reticulated Pythons usually choose to flee if possible, striking only if cornered. A female python guards her eggs, coiling around them and waiting until they hatch. During this time, she will not feed at all. She even incubates them by ‘shivering’, raising her own body temperature (and the temperature of the eggs) above that of her immediate surroundings.

Oriental Whip Snake (Ahaetulla prasina):
This long, slender snake is often encountered in trees and shrubs along forest edges and in parks and gardens. Its slender body enables it to venture onto the thinnest twigs as it hunts for its prey, usually geckos and other arboreal lizards, and the bright green coloration provides excellent camouflage amongst the vegetation. The Oriental Whip Snake has good binocular vision, and oddly enough, its eyes possess horizontal, keyhole-shaped pupils. This snake has small fangs at the rear of its mouth and is mildly venomous, but it is inoffensive, and usually quickly slithers off if threatened.

Paradise Tree Snake (Chrysopelea paradisi):
Like the Oriental Whip Snake, the Paradise Tree Snake is a diurnal, arboreal hunter that can be commonly found not just in forested areas, but also in suburban and urban green spaces. It hunts geckos, frogs, and sometimes small birds and bats, immobilising its small prey with venom delivered via small fangs at the rear of its upper jaw. It has an interesting adaptation – it belongs to a group of Southeast Asian snakes that can actually glide! By leaping off tall trees, and flattening out its underside into a concave shape while undulating its body as if it’s swimming through the air, the Paradise Tree Snake generates air resistance and lift. In this manner, this species of snake can glide up to 100 metres to another tree, although this tends to end with a not so graceful crash landing. This enables the Paradise Tree Snake to travel easily from tree to tree without spending all the energy on climbing, or risking an attack from predators on the ground.

Bottom Row (L-R)

Twin-barred Tree Snake (Chrysopelea pelias):
Red with black-edged white bars, this is a beautifully patterned snake that is rarely seen. It is mostly restricted to forests in and around the Bukit Timah Nature Reserve and Central Catchment Area. Like its close relative the Paradise Tree Snake, the smaller Twin-barred Tree Snake has the ability to glide from tree to tree. It too is mild-tempered and unlikely to bite, reserving its venom for subduing prey such as geckos and other arboreal lizards.

Wagler’s Pit Viper (Tropidolaemus wagleri):
Also known as the Temple Viper, this is the snake commonly seen at the famous Snake Temple in Penang. In Singapore, however, this is a forest-dependent species that is mostly found in the Bukit Timah Nature Reserve and Central Catchment Area. Almost wholly arboreal, this snake is mostly likely to be found coiled up amongst the branches in low shrubs and trees, anchoring itself with its prehensile tail. Interestingly enough, this species has sexual dimorphism; adult females have different colour patterns from adult males (this specimen is an adult female). Unlike other snake species, which can be found actively slithering about in search of prey, Wagler’s Pit Viper is quite sedentary, and can be often found on the same branch for days. This is a member of the group known as pit vipers, which possess a special heat-sensing pit between the eye and nostril on both sides of the head. Like in pythons, these pits enable the viper to sense warm-blooded prey such as rodents and birds, although geckos may also be taken. A sit-and-wait predator, Wagler’s Pit Viper simply waits for prey to wander within striking range. Vipers have fangs that fold back when not in use, but swing forward to deliver the venom when the snake bites into something. Viper venom is predominantly haemotoxic, and can destroy red blood cells, disrupt the blood’s ability to clot, and cause general tissue damage. Unlike many other Asian viper species, Wagler’s Pit Viper is not aggressive, and its venom is considered to be less potent, with most bites resulting in pain and localised swelling. Getting bitten by one certainly warrants immediate medical attention, but you’re not in great danger of dying.

Blue Malayan Coral Snake (Calliophis bivirgatus):
This is another beautiful forest species, but one that is best admired from a distance. Sometimes seen crossing forest trails or slithering across the forest floor, this snake specialises in hunting other snakes! When confronted, the Blue Malayan Coral Snake may flip over onto its back, flashing its red underside, or hide its head in the leaf litter or under one of its coils while flicking its bright red tail as a distraction. However, despite such a timid nature, it is certainly not to be messed with. The bright red head, tail, and belly, and the bright blue flank stripes make this a highly visible creature at close range, and it is likely that this serves as a warning to potential predators – attacking this snake might prove to be a costly and fatal mistake. A member of the family of front-fanged venomous snakes known as elapids, the Blue Malayan Coral Snake counts other highly venomous snakes such as cobras, kraits, and sea snakes as among its close relatives. Its venom is neurotoxic, with victims suffering from numbness and paralysis, and subsequently respiratory failure as the nervous system shuts down. In fact, another forest snake, the Pink-headed Reed Snake (Calamaria schlegeli), is thought to defend itself from predators by having a similar colour pattern, and hence mimicking the truly lethal Blue Malayan Coral Snake, despite not having any venom at all.

These were some of the many specimens featured at the recently concluded Festival of Biodiversity 2014, which was held at VivoCity last weekend.

Three very common non-native vertebrates of Singapore:

Green Chromide (Etroplus suratensis) (Left)
This native of river estuaries and coastal lagoons of southern India and Sri Lanka was first recorded in Singapore in 1995. Since then, it has spread to many coastal areas of Singapore. It’s possible that it was introduced to our waters through escaped or released pets, as the species has been imported in the past for the aquarium trade. Another possible route of introduction is dispersal from southern Johor, where feral populations of Green Chromide also exist. The Green Chromide is a member of the cichlid family, and several other species have also become established here. For instance, Tilapia (Oreochromis spp.) from Africa and the Mayan Cichlid (Cichlasoma urophthalmus) and Midas Cichlid (Amphilophus citrinellus) from Central America are now widespread and abundant in many urban waterways, whereas South American Peacock Bass (Cichla orinocensis) and Eartheater Cichlid (Geophagus altifrons) can be found in several of our ponds and reservoirs. Man-made hybrids commonly called Flowerhorn Cichlids or Luohan are also now present in many locations, due to irresponsible owners abandoning their pets.

Changeable Lizard (Calotes versicolor) (Upper Right)
This lizard is commonly found in open areas such as parks, gardens, roadside vegetation, and scrubland, where it may be seen basking on tree trunks and fences. Able to change the colour of skin to aid in camouflage, the Changeable Lizard is sometimes mistakenly called a “chameleon”. During the breeding season, male Changeable Lizards develop bright orange heads with a large black blotch on the cheek and throat, displaying to females and rival males by nodding their heads and doing push-ups. This lizard, which is widely distributed through much of mainland South and Southeast Asia, was first recorded in Singapore in the 1980s, and likely reached our shores due to accidental transportation of stowaways in cargo and goods from Thailand and the northern states of Peninsular Malaysia. Since then, however, it appears to have displaced the native Green Crested Lizard (Bronchocela cristatella), which used to be commonly seen in urban green spaces. Today, the Changeable Lizard has taken over many of the areas once occupied by the Green Crested Lizard, with the latter largely restricted to forests.

Red-eared Slider (Trachemys scripta elegans) (Lower Right)
The turtle species most commonly seen for sale in local pet stores, this native of the Mississippi River drainage in the United States has been introduced to many areas outside of its original range, often with negative ecological impacts. Rampant abandonment of pets and release of captive turtles as (misguided) acts of religious goodwill mean that the Red-eared Slider is now the most widespread and most commonly encountered turtle species in Singapore, and can be found in large numbers in most urban ponds, reservoirs, and some canals. The large populations seen in some areas are likely to be a combination of continual release of pets, as well as successful breeding in feral turtles. It is possible that the sheer number of Red-eared Sliders has an impact on native turtle species, which may be unable to compete with the Red-eared Slider for resources such as food and basking and nesting sites.

These were some of the many specimens featured at the recently-concluded Festival of Biodiversity 2014, which was held at VivoCity over the weekend.

Various marine invertebrates of Singapore:

Neptune’s Cup Sponge (Cliona patera)
This huge sponge is shaped like a wine glass, and can grow up to a metre in height and diameter. First described from specimens collected from Singapore in 1822, and heavily harvested in the 19th century for museums and private collections, this huge sponge was last recorded locally in the 1870s. After more than a century without any new sightings, it was feared to have become extinct. However, the species was rediscovered in 2011, when a couple of juvenile sponges were discovered in the waters off St. John’s Island, and only the second time the Neptune’s Cup has ever been observed in-situ. It is possible that there are more of these sponges, even adults, waiting to be discovered in our waters.

Knobbly Sea Star (Protoreaster nodosus)
This is one of Singapore’s largest sea stars, and can be found in seagrass and coral rubble and adjacent sandy areas. Where conditions are right, these sea stars may be densely distributed, with up to 50 individual sea stars per 100 square metres of seagrass habitat. Individuals may vary in appearance, and differ in colour, number of arms, and arrangement of knobs, which are thought to play a role in defending the Knobbly Sea Star from predatory fishes. It appears to feed heavily on microbial films and tiny creatures living on seagrasses and in the sediment, but it has also been known to consume smaller marine animals such as sponges, corals, sea anemones, molluscs, and echinoderms, as well as scavenge on carrion and decaying plant matter. Threatened by habitat loss, and now considered locally Endangered, scattered remnant populations still exist in shallow waters around Pulau Semakau, Cyrene Reef, Chek Jawa, Pulau Sekudu, Beting Bronok, among others. Sadly, because juveniles have yet to be recorded for most of these shores, it is not known if all of these locations contain self-sustaining, reproducing populations. Elsewhere in the region, widespread and intensive collecting for the trade in dried sea stars as souvenirs may have a significant impact on the species.

Mud Lobster (Thalassina sp.)
This extremely shy crustacean lives underground in the back mangroves, where it excavates an extensive network of tunnels while feeding on organic matter in the mud. All this digging creates large volcano-like mounds that may reach up to 2 metres in height! Many other mangrove creatures end up using this network of mounds, burrows, and tunnels. The tunnelling brings organic matter from deep underground to the surface, and also allows oxygen to penetrate the otherwise oxygen-poor mud. Some mangrove plant species appear to benefit from Mud Lobster activity, and are often found growing on and around their mounds. As a result, the Mud Lobster is seen as an important component of the mangrove ecosystem.

Coastal Horseshoe Crab (Tachypleus gigas) & Mangrove Horseshoe Crab (Carcinoscorpius rotundicauda)
The four living species of horseshoe crabs are often called prehistoric survivors, as fossils very similar to the modern-day species have been found in rocks that predate even the Mesozoic, when the dinosaurs evolved. These bizarre arthropods are not crustaceans, and hence aren’t actually crabs. Instead, they belong to another group called the chelicerates, which also includes arachnids such as spiders, scorpions, and mites. They are harmless; the long tail (also called a telson) is often mistaken for a dangerous weapon, but is mostly used as a rudder to steer the horseshoe crab when it’s swimming underwater (often upside down), or as a lever to right itself if it’s been flipped over. Horseshoe crabs feed on other benthic organisms, including tiny worms, molluscs, and crustaceans, and will also scavenge. Food is ground up using thick bristles at the base of the legs, where the mouth is also located. Horseshoe crabs are often encountered as breeding pairs, with the smaller male clinging to the carapace of the female with enlarged front legs. Sadly, they are heavily collected in many parts of their range for human consumption, and in recent years, for pharmaceutical use, as an extract from horseshoe blood is used in testing for bacterial contamination of pharmaceutical products and medical equipment. Locally, habitat destruction is a major threat, while entanglement in fishing gear such as abandoned fishing nets and fishing lines takes its toll as well.

Two species of horseshoe crab are found in Singapore, differentiated mostly by morphology and habitat preference.

The Coastal Horseshoe Crab tends to be greyish-coloured, grows to a larger size, and has a tail that is triangular in cross-section with a serrated upper edge. It has been seen at locations such as Changi, East Coast Park, Pulau Ubin, and Sentosa, and is found mostly along sandy shores, often close to reefs and seagrass beds. Widespread coastal reclamation and other development works have led to this species becoming locally Endangered. In other countries, the roe of this species is consumed, and has led to overexploitation.

Smaller, more brownish in colour, and with a tail that is rounded in cross-section with a smooth upperside, the Mangrove Horseshoe Crab is found mostly in mangroves and mudflats, but may also be found in nearby areas with silty or other soft substrates. Locations where this species has been recorded include Pulau Ubin, Kranji, Sungei Buloh, and Mandai Mudflats. In fact, the mudflats of northwestern Singapore are an important breeding ground for this locally Vulnerable species. Consuming the roe of this species can be a fatal mistake, as the Mangrove Horseshoe Crab can contain lethal amounts of tetrodotoxin, the same toxin found in pufferfishes!

These were some of the many specimens featured at the recently-concluded Festival of Biodiversity, which was held at VivoCity over the weekend.