Friday, September 7, 2007

Ecosystem - Coral Reefs

Question Time:What is your favourite seafood? Name them.

Link your answer to introduce the first Naked Fact!

Naked Facts:

NF#1: City under the sea!
a) Coral reefs are homes/shelter to nearly one quarter of all known marine species. They include over 4000 species of fish, 700 species of coral and thousands of other forms of plants and animal life.
b) Seafood like groupers, snappers, grunts, wrasses and many more will be gone if coral reefs disappear. Now we won't want that, right?

More information about Corals, click here.

Wednesday, September 5, 2007

Ecosystem - Mangroves

Naked Facts:

NF#1: Read them from here !
Great and important facts! Do read them.

NF#2: Seagrasses need the mangroves.
a) Mangroves can slow down the speed of water from inland, therefore causing fine silt to settle around the mangrove forests.
b) But if these fine silt reach the waters, they will cloud the water, block the sunlight and the seagrasses will not be able to make food (photosynthesize) and flourish.

NF#3: No durians with mangroves?Read more about this here.
Did you know?
It is believed that the earliest species of mangroves came from the Southeast Asian region.
There are more mangrove species in this region than anywhere else in the world.

Too much information
NF#4: Pollution Controller
a) Mangroves help to control some forms of pollution, including excess amounts of nitrogen and phosphorous, petroleum products, and halogenated compounds from reaching the seas. Mangroves stop these contaminants from polluting the ocean waters through a process called rhizofiltration. But the over-existence of these pollutants can kill the mangrove trees.
b) Rhizofiltration is the filtering of water through a mass of roots to remove toxic substances or excess nutrients.

For more reading on the importance of mangroves, you may click here.

Related Links:
1. Mangrove Climbers
2. Bushes in the mangroves

Ecosystem - Coastal Forest of Chek Jawa

Naked Facts:

Interactive Question:
Question: Now let's observe, can you find any differences between the coastal forest and mangrove forest?

Possible Answers:
1) The mangrove forest is sometimes submerged in seawater while the coastal forest is not submerged in water.
2) The roots of the mangrove trees have weird roots (you can talk more about them at the mangrove forest) while the trees at the coastal forests do not.

NF#1: Source of Nutrient AKA Food for marine life at the shore
a) When it rains, nutrients from the soil, fallen leaves etc and minerals from the rocks are washed down the slopes of the coastal forest
b) These are in fact considered ‘food’ for many marine flora and fauna living in the inter-tidal zone.

NF#2: Natural wind buffer
a) Imagine a natural wall which is steep and built up of rocks and vegetation.

b) It helps to lessen the impact of strong winds from storms, hurricanes etc.

NF#3: Place to find
rare and unique plants + jungle fowl
a) The plants you find at coastal forests can be given the titles of ‘survivors’,
as they are constantly exposed to strong dry winds, salt sprays, the hot temperature.
b) Due to development, we do not have a lot of places left in Singapore with coastal forests now, think Labrador Park, Sentosa and Chek Jawa.
Native Jungle fowls are also known to live the coastal forest of Chek Jawa.
d) Some rare/unique plants found at the coastal forest include the Seashore Nutmeg, Pong pong tree and Delek air tree etc. Read more about them here.

More reading:
To read on showy and interesting plants found at the Coastal forest, click here.

Simple Drawing on coastal forest ecosystem, worth a look!


Monday, August 20, 2007

The Great Flood at Chek Jawa

NF#1: In January 2007, Singapore experience some of the heaviest rainfall in 75 years. The rain was just as severe in Johor, and the Johor River was bloated with rain water, which it eventually released into the Straits of Johor.

NF#2: On 18 January 2007, there was a public walk at Chek Jawa, and Adelle from Nparks informed the other regular guides that a lot of animals have died. We suspected that due to the heavy rainfall, Chek Jawa was flooded with freshwater, and it is known that most marine animals could not survive well in water with low salinity. Animals like the carpet anemone simply exploded from taking in too much freshwater, others like sea stars and sponges turned black and died, and many of the snails just died and decomposed into black liquid in their shells.

An exploded carpet anemone.

A dead knobbly seastar.

A decomposed noble volute.

NF#3: Kok Sheng from NUS is conducting a study on the mass mortality and recruitment of macrofauna for example like carpet anemones. This project also lays the foundation for the long-term monitoring and understanding of Chek Jawa.

More information at:
- 18th January
- Death Note from Chek Jawa
- First TeamSeagrass Field Orientation at Chek Jawa
- Chek Jawa Mortality and Recruitment Project

Chek Jawa Boardwalk

NF#1: The CJ boardwalk was constructed in about 18 months, but the impact on the rich seagrasses and sandflats was minimal. This is because the barge only brought in the construction material for the workers to do the piling during high tide, and when the tide got lower, it returned to deeper waters.

Interesting note: We started seeing oysters, mussels and barnacles on the pillars just weeks after they were placed! And we had seen healthy sea anemones growing just next to the pillars! The public walks were only suspended when the floods in January 2007 caused the massive mortality.

Question for Visitors: What material do you think the boardwalk is made of?

NF#2: While the boardwalk looks like it was made from wood, it was actually made from concrete and fibre glass! The mold used to make the boardwalk was made based on real wooden planks.

NF#3: The entire boardwalk is 1.1km long and has 2 sections - the coastal section (600m) and the mangrove section (500m).

Friday, August 17, 2007

Legend of Ubin and Pulau Sekudu

Naked Fact #1:
Three animals from Singapore -- a pig, an elephant and a frog -- had a challenge to see who would reach the shore of Johor first. Whichever animal that failed to reach the shore would be turned into rock. All three creatures had difficulties swimming the Straits and the frog turned into Pulau Sekudu, while both the pig and the elephant changed into one big rocky island - Ubin.

Naked Fact #2:
Pulau Ubin is originally bisected down the middle by the river Sungei Jelutong. However, due to prawn farming over the decades, the island has been joined together by the mud bunds across the river that form the prawn ponds. Perhaps that would explain why 2 animals form the bulk of Ubin.

Naked Fact #3:
The islet off Ubin that can be seen from Chek Jawa is named Pulau Sekudu which means Frog Island. There is a rock on Pulau Sekudu that resembles a frog. In fact, a smiley face has been painted on the "face" of the rock. However, it looks most like a frog from its side profile.

CARE Message:
Understand and respect the tides.
Pulau Sekudu, like much of the inter-tidal areas of Chek Jawa, is only accessible at low tide. However, the tides can be unpredictable and dangerous especially when the tide is rushing in. The water level can suddenly increase and you can be trapped on the fast-submerging islet before you know it. Accidents have been known to happen so it's always important to check tide tables before going out to shore areas. Safety first!

Jejawi Viewing tower

NF#1: The tower is 20m tall and allows visitors to get a good view of Chek Jawa and the surrounding areas. Due to it's height, the tower is also a great place to spot birds on nearby trees. This tower can take a maximum of 40 people.

NF#2: The Jejawi Tower is named after the Malayan Banyan (Ficus microcarpa) growing nearby that was as tall as the tower. The Malayan Banyan is a fig tree. 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.

Interesting Note: To connect visitors to figs, guides who understand Chinese can ask the visitors if they know the popular oldies "榕树下"(pronounced as Rong Shu Xia), which means "Under the Banyan Tree". Or has anyone eaten "无花果"(pronounced as Wu Hua Guo), which is also a fig. Do explain to the visitors that "无花果" actually do flower, just that the flowers are concealed within the fig. And what they are eating is not really the fruit, but a natural container for the flowers and seeds!

Too Much Information:

Figs are pollinated by tiny fig wasp that are mostly smaller than the head of a pin!

The female wasp somehow finds the correct fig tree in bloom, and sometimes, she must fly a long long way!

To get to the flowers, she squeezes through a tiny little hole in the fig. In the process she loses her wings and most of her antennae.

Usually, there are 3 types of flowers inside the fig:
1. Male flowers near the tiny hole
2. Female flowers with short styles
3. Female flowers with long styles

The male flowers are still immature without pollen. As the female wasp moves around in the fig, she transfers pollen she collected from her previous fig to the female flowers.

She will lay eggs in the female flowers with short styles. After laying the eggs, she dies.

After some time, the baby wasps hatch and feed on the plant tissue surrounding them. The males will hatch first. They are wingless but have strong mouth parts.

Meanwhile, the female flowers with the long styles develop seeds.

Once the male wasps become adults, they will seek out the female wasps and mate with them. After mating, the male wasps will chew and enlarge the tiny hole to create a wider tunnel so that the females can depart without losing their wings. The males usually die soon after they enlarged the tunnel.

As the females leave the fig, they pick up pollen from the male flowers that are now mature.

After they leave, the fig ripens and the walls become yummy to eat. Animals eat the fig and disperse the seeds.

Meanwhile, the brave little female wasp flies on to start the whole cycle then starts all over again.

Additional info on fig and fig wasp:
- The Fib Web
- The Last Stand of the Male Fig Wasp
- One Fig, One Wasp? Not Always!

Wednesday, August 15, 2007

House No. 1 - Chek Jawa Visitor Centre

NF#1: The Chek Jawa Visitor Centre is also call House No. 1, which is its postal address in Pulau Ubin. This unique building was built in the 1930s for Langdon Williams, the then Chief Surveyor, as a holiday retreat. It is made of masonry and emulates the style of an English cottage, first found in tea planters’ residences during the British colonial era. The building was awarded conservation status on 1 December 2003, and restoration work of the building was completed in 2006.

NF#2: House No. 1 is also the home to rare 2 species of rare bats! The fireplace, which is among the last few working ones left in Singapore, is the home to a colony of rare Pouched Tomb bats. The nearby water tower was retained as another rare species of Malayan False Vampire bats currently resides in it.

NF#3: There used to be another smaller outbuilding. Although newer than the main house, it had to be pulled down as it was no longer structurally sound. Some of its wall facades have been salvaged and incorporated into the toilet block.

Tuesday, August 14, 2007

Slithery Snakes

Naked Facts (General information about snakes):
  • All snakes are carnivorous or you can say they only eat meat.
    • Some snakes have a venomous bite, which they use to kill their prey before eating it.
    • Other snakes kill their prey by constriction or called 'wrapping you up and then squeezing you to death'.
    • Still others swallow their prey whole and alive.
  • Snakes are covered in scales. Most snakes use specialized belly scales to travel, gripping surfaces.
  • They shed their skin periodically. The primary purpose of shedding is to grow; shedding also removes external parasites.
  • Venom VS poison: The term poisonous snake is mostly false - poison is inhaled or ingested whereas venom is injected. A venomous snake is a snake that uses modified saliva, venom, delivered through fangs in its mouth, to immobilize or kill its prey.
Too Much Information:
  • Unlike other reptiles, shedding for snakes is usually done in one piece, like pulling off a sock, with the snake rubbing its nose against something rough, like a rock, for instance, creating a rip in the skin around the nose and the mouth until the skin is completely removed.
  • It is a common misconception that snakes actually dislocate their lower jaw to consume large prey. Actually as snakes do not chew their food and have a very flexible lower jaw, the two halves of which are not rigidly attached, and numerous other joints in their skull, allowing them to open their mouths wide enough to swallow their prey whole, even if it is larger in diameter than the snake itself.

Fabulous four (Mangrove) snakes:

Common Characteristics:

  • All of them are aquatic.
  • Their eyes are positioned on the top of their heads so that they can remain with their body submerged in water and yet are able to see above the surface.
  • All of them have poisonous fangs on the back of their jaws, but their venom is not known to have any serious effects on humans.
  • All of them give birth to living young, and appear to be largely nocturnal in habits.

Dog-faced Water snake or Bockadam, Cerberus rynchops feeds largely on fish trapped in mud puddles during the low tide.

Yellow-lipped Water snake, Gerarda prevostiana, is less common. It specialises in feeding on newly-moulted crabs.

Cantor’s Water snake, Cantoria violacea, is a rarely seen and extremely long species with markings similar to that of the venomous sea snakes (family Elapidae, or Hydrophiidae). It feeds on snapping shrimps.

Crab-eating Water snake, Fordonia leucobalia, is believed to live mainly in mud-lobster mounds and feeds on hard-shelled crabs.

Monitor Lizards: Cleaner of the Mangroves

Naked Facts:
  • Monitor lizards are the “cleaners” of the mangrove habitat as they eat anything that they can swallow therefore helping to make sure there is no too much of any living things in the mangrove.
  • Their long list of 'diet' consists of (here goes): tiny insects, crabs, molluscs, snakes, eggs (of birds and crocodiles), fishes (including eels up to 1m long), rodents, small mouse deer, other monitor lizards and even human faeces. But they are particularly fond of dead bodies.
  • They have known to eat prey almost as big as themselves: a 1.2m long monitor lizard ate a snake 1.3m long.
  • Corny Joke: As long you try not to look ‘delicious’, they are not known to consume humans.
  • Message behind joke: Observe but not disturb them.
  • The Water Monitor's main hunting technique is to run after prey that it has spotted, rather than stalking and ambushing.
  • Like snakes, they have a forked tongue that they stick in and out regularly to "smell" their prey and other tasty titbits.
  • Water Monitor Lizards are highly mobile. They can swim, run faster than most of us can run and even climb trees.
  • Monitors can survive in habitats (such as the mangrove forests) that wouldn't be able to support other large carnivores as they are cold blooded (If you need to drag time, you might want to explain the difference between warm and cold blooded).
Did you know?
  • Komodo Dragons are a member of the monitor lizard family, Varanidae.
Too Much Information:
  • They have been seen swimming far out at sea and can remain underwater for up to half an hour.
  • They climb to search for food as well as to escape predators. The young usually stay in trees for safety. If cornered up a tree, they will jump into the safety of a stream or river.
  • As scavengers, Water Monitors keep the habitat neat and tidy, and also control populations of their prey. They in turn provide food for larger carnivores such as crocodiles and birds of prey. Small young Water Monitors are particularly vulnerable even to large birds such as herons.
More about the Monitor Lizard.

R(A) link (Watch how two monitor lizards mate):

Vinegar Crabs aka Tree Climbing Crabs

Name the Creature Activity (Something you can try with kids if a Vinegar Crab is spotted on a tree):

Guide: "Hey, we have a crab on a tree here (point to crab)."

Guide: "Let's say we want to name this crab, what name would you give it?"

Kid A: "Tree crab?"

Guide: "But how did it get up there?"

Kid A: "Climb! Oh, Tree-climbing crab!"

Disclaimer: Might not work every time.

Naked Facts:
  • During low tides, you can find them on the forest/mangrove floor feeding on leaves.
  • During high tides, you can usually find them at a height high enough to clear the water level and they will remain motionless on tree-trunks, leaves or boardwalk legs.
  • This is probably a predator-avoidance behaviour, especially with the many predatory species of fish and crabs that hunt with the incoming tide. Out of the water, they remain motionless to avoid other predators like kingfishers, monitor lizards and otters.
  • At night time or dusk, they have been seen climbing up trees to heights of more than six meters to graze on algae as well as eating leaves.
  • Food fact (1): The Teochew are known to pickle this crab in black sauce with vinegar, and take it with porridge. That’s why they are also called vinegar crabs.
  • Food fact (2): The Thais like it salted, with the roe or simply fried whole.
  • National Education: There is a tree climbing crab named the Singapore vinegar crab (E. singaporense), it is a common species of the tree climbing crab (Episesarma) and has entirely red claws. It is commonly sighted in or near mud lobster mounds.
Too Much Information:
  • They are usually burrowing crabs, digging holes at the base of trees and mud lobster mounds.
  • They are considered pests of mangrove plantations for their habit of attacking propagules (seeds of the Lenggadai, a threaten species of mangrove).
  • Tree Climbing Crabs are known to scavenge meat like many other crabs.
Reference and more about Tree Climbing Crabs

Monday, July 30, 2007

Teaching Nature-Study

Extracts from "The Handbook of Nature Study" by Anna Botsforc Comstock. Written in 1911, the principles she lays out remain fresh and relevant nearly 100 years later!

What Nature-Study Is
Nature-Study is a study of nature; it consists of simple, truthful observations that may, like beads on a string, finally be threaded upon the understanding and thus held together as a logical and harmonious whole. The object of Nature-Study should be to cultivate in children the powers of accurate observation and to build up within them understanding.

What Nature-Study Should Do for the Child
Nature-Study cultivates the child's imagination, since there are so many wonderful and true stories that he might read with his own eyes. At the same time, Nature-Study cultivates in him a perception and a regard for what is true, and the power to express it.

Perhaps half the falsehood in the world is due to lack of power to detect the truth and to express it.

Nature-Study cultivates in the child the love of the beautiful; it brings to him early a perception of colour, form and music.

But, more than all, Nature-Study gives the child a sense of companionship with life out-of-doors and an abiding love of nature.

Let this latter be the teacher's criterion for judging his or her work. If Nature-Study as taught does not make the child love nature and the out-of-doors, then it should cease. However, if the love of nature is in the teacher's heart, there is no danger.

When and Why the Teacher Should Say "I Do Not Know"
No science professor in any university, if he be a man of high attainment, will hesitate to say "I do not know" if they ask for information beyond his knowledge. The greater his scientific reputation and erudition, the more readily, simply, and without apology, he says this.

It is only the teacher in the elementary schools who has never received enough scientific training to reveal to her how little she does know, who feels that she must appear to know everything or her pupils will lose confidence in her.

In Nature-Study, any teacher can with honour say, "I do not know".

But she should not let lack of knowledge be a wet blanket thrown over her pupil's interest. She should say frankly: "I do not know; let us see if we cannot together find out this mysterious thing. Maybe no one knows it as yet, and I wonder if YOU will discover it before I do".

The Use of Scientific Names
This matter is of little importance if the teacher bears in mind that the purpose of Nature-Study is to know the subject under observation and to learn the name incidentally.

If the teacher says, "I have a pink hepatica. Can anyone find me a blue one?" the children, who naturally like grown-up words, will soon be calling these flowers hepatica.

But if the teacher says, "These flowers are called hepaticas. Now please everyone remember the name. Write it in your books as I write it on the blackboard, and in half an hour I shall ask you again what it is," the pupils naturally look upon the exercise as a word lesson and its real significance is lost.

How To Use the Book
Make the lesson an investigation and make the pupils feel that they are investigators. To tell the story to begin with spoils this attitude and quenches interest.

And lots more in the book including
What Nature-Study Should Do for the Teacher
Nature-Study as a Help to Health
Nature-Study as a Help in School Discipline
The Relation of Nature-Study to Science
The Child Not Interested in Nature-Study
The Correlation of Nature-Study with Language Work
The Correlation of Nature-Study and Drawing
The Correlation of Nature-Study with Geography
The Correlation of Nature-Study with History
The Correlation of Nature-Study with Arithmetic

Sunday, July 29, 2007

Techniques for reawakening love for nature

Extracts from "The Lost Language of Plants" by Stephen Harrod Buhner (a great book that you should try to read if you can, I have a copy).

"Human beings, throughout most of their habitation of Earth, have been so completely interwoven into their environment that, until recently, there was no separation between them."

"Such deep interconnectedness to environment is so fundamental to us as a species that, ultimately, it is not possible to understand ourselves as human beings without understanding something of wild nature itself."

"Because experience of nature and other life-forms is so deeply interwoven into our emergence as a species, human beings possess a genetic predisposition for wild nature and other life-forms -- though it must, through specific experiences, be activated".

"Edward Wilson calls this innate feeling or caring for living forms and systems, for nature, biophilia."

"There are holes inside all of us. Emptiness that can only be filled by some of the other life on this Earth. Without filling them, we live a half-life, never becoming fully human, never being healed or whole or completely who we are. Never becoming completely sane."

"The loss of connection to the land, to Earth, leaves the holes with which we are naturally born unfilled. Merely human approaches can never heal them. Pathologies come from the empty hole that are unfilled, from lack of contact and communication with the wild."

"The holes within us possess particular shapes -- that of stone or tree or bear."

"Many people believe we should first establish this reconnection in the young. But I think that the best hope for restoring it is with the grown -- those in whom the impulse for biophilia has been stunted, those in whom the interior wound is deep, those in whom the need is the greatest."

"If simple information were enough to stimulate the experience, a book will do as well. But books do not and cannot do as well."

"Licensed teachers are embedded in a human-centric, we're-the-most-intelligent approach. They are likely to belittle the living reality found in nature."

"The teacher must embody the experience itself, so that the child can observe it in action and the teacher teaches."

Techniques for restroring biophilia

"The restoration of our capacity for biophilia begins with restoring, and supporting, our capacity for feeling."

"Restoring biophilia ... means 'coming to our senses', especially the sense of feeling -- of touch -- of being touched by the world."

"It has nothing to do with theory. Feelings come first, thinking second; thinking in service of feeling."

"This experience cannot be written down or found in books. It can only be developed ... by allowing ourselves to be touched by the livingness of the world, and exploring the meanings we encounter."

"This reconnects us to everything around us -- to everything that generates those feelings. It reweaves us into the fabric of life."

There are 9 exercises in the book, here is one of them.

Exercise 3

Go to a place in nature that you like. (Be sure and take a journal with you.) Choose a place you have been to before. Find the area that you like most and relax. Sit if you want to; get comfortable.

How does this place feel? Try to describe it in words. Be as specific as you can. Go on in your journal at length if you need to. Write down everything that comes to you no matter how silly it sounds. Even if you think it's crazy.

When you're done, allow your eye to rove, to be drawn to whatever one thing is most interesting to you. Look at it. Let your eye explore it, nothing everything about it. The colours, the shape, how it rests or grows in the ground. Its relation to the air around it, to the plants, water, soil, rocks around it.

What feelings do you have? Write them down.

Is there any part of what you are looking at that you like more? Less? Why? Can you tell? Do all parts of what you are looking at generate the same emotion? Different emotions? Write everything down in your journal.

Do this with at least two things that you see. Make sure that one of them is a plant. You can get up close if you want to, place your eye on a level plane, take an insect view. How is the plant shaped, how does it feel to your fingers, how does it smell? What emotions does it generate in you? Write everything down.

Now go to another natural place, different from the first. Sit down and relax. Get comfortable. How does this place feel? Write down everything that you notice. Go on at length.

Does this second place feel different from the first place you sat? How are the feelings different? Which place feels better -- the first or the second? Is there a name you can give the feeling you had at the first place? A name you can give the second? Names that will make clear the difference in feeling that you perceive? If you can't think of a word make something up.

When you are finished, as you did last time, find something your eye is drawn to and write down everything that you feel and perceive. Do this as well with two other things, at least one of them a plant.

Each place on Earth has unique feelings associated with it, as does each thing that grows or resides there. The number of shadings of their emotional nuances run into the thousands. Each can fit into a specific space within the different human beings that need them. There is a richness in feeling, a companionability that comes from perceiving, the complex interweaving of emotional textures that reside in the life that surrounds us.

Thursday, July 26, 2007

Half a beak is better than none?

The halfbeak is so named because its lower jaw is much longer, while its upper jaw is short and triangular. "Hemi" means half; while "rhamphos" means beak or bill in Greek. The jaws have several rows of small teeth and the tip of the long, spike-like lower jaw is often brightly coloured. The eyes are relatively large and scales are large too.

Halfbeaks are well adapted to living at the water surface. Usually darker on the top while the sides and underside are silvery. This camouflages it from above-water predators looking down on it, as well as underwater predators looking up at it. Its unfish-like body shape also means it is often dismissed as floating sticks. Some small ones are brown and twig-like.

Halfbeaks eat things that float on the surface such as algae, tiny animals like zooplankton and other fishes. Some halfbeak species eat land insects that might fall into the water, while others eat seagrasses and algae.

Snails and clams of the mangroves

Telescopium snail (Telescopium telescopium) Family Potamididae

It is also called 'Rodong' or 'Berongan' in Malay. 8-15cm. It can stay out of water for long periods of time. It eats detritus and algae, using its highly extendable proboscis to gather edible bits from the mud surface at low tide. It is eaten in some places and is said to be delicious when steamed and eaten with chilli.

Belongkeng snails (Family Ellobidae)

Ellobium sp. on the left is usually found on the ground.
Pythia sp. on the right is sometimes seen on leaves of mangrove trees.
These snails are sometimes seen on leaves and trunks of mangrove trees or on the mud in the back mangroves. They are sometimes also called Mangrove helmet shell snails. Empty shells of dead snails are sometimes also washed up on shores near mangroves.

1-5cm. Shells thick. They breathe air (instead of through gills like most other marine snails) and all lack an operculum to seal the shell opening. They graze on algae growing on mangrove trees and debris.

Mangrove jingle clam (Enigmonia aenigmatica) Family Anomiidae

Like shiny scales, these bivalves are common seen on leaves, trunks and roots of mangrove trees. They usually settle at a height between the high spring and high neap tide.

To about 3cm. The two-part shell is thin and lustrous. Usually oval, sometimes irregular. Colours range from beige, purplish to blackish.

One valve is stuck to a hard surface (leaves, tree trunk, roots) and this valve is usually flat. The other valve is usually slightly conical in shape. The valve that is stuck to the hard surface has a notch or hole in it. The animal secretes byssus threads through the hole to stick to the hard surface. A young animal is more mobile and can move around by using its extendible foot. A young animal is relatively broader than a more mature animal.

Fiddlers: macho crabs of the shore

The Big Useless Claw Story
Messages: "every inch of the shore is alive, every step kills, stick to the death zone"

For a shore walk (you can go straight to Step 3 if you're on a boardwalk)
Step 1: "Stay very still and you will see some interesting animals on the sand. They are very small and very sensitive to your footsteps. If you wave your arms around they will think you are a bird and will hide. Pretend you are a tree and they will come out."

This will make visitors get used to not stomping around. To be still and look carefully for small things that will only come out when there is no disturbance.

Step 2: If it's taking a while for the crabs to come out "While we wait, let's look around us and I'll tell you about some of the special ecosystems we can see on Semakau. Meanwhile DON'T MOVE!"

Step 3: Once crabs are active, "How many claws does the crab have?" Eventually someone will say "One".

Step 4: "Actually it has two claws. The big claw is so big that it misses the mouth. It has a much tinier claw that it uses to feed itself. Can you see one feeding?"

Step 5: "Only the male crabs have one big useless claw. The females have two small claws so they can feed twice as fast."

Step 6: "Why do you think the males have one big useless claw?" Usual guesses: to find food, for fighting, for defence from predators. Explain briefly and clearly why these are not the case. Goad them with "Why do all boys have big useless things? Like sports cars?" Eventually someone, usually a girl or a small child, will say "To attract girls"

If the visitors have been very very still, you can say "These tiny crabs are all over the place. You can see some near your feet too! See!!! Every inch of the shore is alive with creatures. Some of them are small and buried in the sand. Every step we take on the shore will most definitely squash something."

For shore walk
"We have designated a trail on the shore. It is a death zone. Just like any nature park in Singapore. At Sungei Buloh or Bukit Timah, we don't walk anywhere we want to but have to stick to a trail. Otherwise, a larger and larger area will become 'botak' as footsteps kill off small plants and animals.

"To minimise this death zone, please stay close to me and try to stay in a single file."

If you are not the first group "Follow the trail made by the group in front. Then you don't kill things that they haven't already killed."

For boardwalk
"It's great to have a boardwalk, so we can have a look at these animals without killing them!"

Tips on dealing with fiddlers

Please do NOT pick up fiddlers. Visitors will do as we do and not as we say. In any case, if we catch them and put them down far away from their burrow, they will be stressed and may not be able to find protection and then die.

Please do NOT dig up fiddlers either. This is destructive to the habitat, and encourages visitors to dig up everything they want to see. Instead, encourage them to be patient and wait for animals to come out and go about their normal business.

Naked Facts:

The male waves his large pincer in a style and rhythm unique to his species in order to attract the ladies. Fiddler crabs got their name for this behaviour, which resembles a musician playing on his fiddle. Interactive activity: You can do the fiddler movement using one of your arms to demonstrate to visitors how fiddler crabs fiddle.

The eyes of a fiddler crab are mounted on long stalk giving it a good all-round view of the air and the horizon. This is for potential mate, rival and early predator detection. When the crab scuttles back into its burrow, the eyestalks fold down into grooves along the body.

Interactive activity: Use two fingers from each hand to illustrate this point.

The larger claw can be its either right or left claw. If an adult male loses its fiddler claw, the remaining claw grows to the same size as the lost claw, the claw it regenerates becomes the smaller claw.

Sex sells: When a male Fiddler crab succeeds in persuading a female to mate with him, they retire into his burrow. The female may remain there until the eggs hatch. The eggs hatch into free-swimming larvae that drift with the plankton, changing into yet another form before settling down and developing into fiddler crabs.

Too Much Information

Fiddler crab species are distinguished by the structure of the male's enlarged pincer. They are not reliably distinguished by the colour of bodies, pincers. The species of females is hard to distinguish.

Fiddler crabs cannot swim and prefer to breathe air. So at high tide, they hide in their burrows, plugging the entrance with a ball of sand to trap some air inside. However, they need water to keep their gill chambers wet as well as to process their food. They absorb water from the wet sand through hairs on their legs.

Porcelain fiddler crab (Uca annulipes)

Distinguishing features of the enlarged pincer of the male
  • outer side is smooth and does not have a triangular depression (most observable difference)
  • the movable upper finger extends past the immobile lower finger.
  • has a ridge of bumps on inside or the 'palm' of the pincer.

Orange fiddler crab (
Uca vocans)

Distinguishing features of enlarged pincer of the male

  • has a bumpy outer face.
  • the tips of the claws are flattened and sabre-like.
  • the immobile lower finger has a long groove on the outside.

Mudskippers: frog, snake or fish?

Thoughtful question: "Is it a fish, a snake or a frog?".

Fish! "Yes, it's a fish. But how can it move around out of water? How do you think it breathes out of water?"

"How do YOU breathe underwater when you go diving?"

"Just like the way we bring two tanks of air for scuba diving, the fish brings two tanks of water in its gill chambers. Which is why it has such 'puffy cheeks'."

Naked Facts

Mudskippers have to regularly replenish the water in their gill chambers, so they cannot stay far from water. But mudskippers can actually ‘breathe’ (absorb) air through their skin (as long it remains moist) . This is why they often roll in puddles and keep their tails in water, leading some early observers to believe that mudskippers breathed through their tails!

Mudskippers skip by flipping their muscular bodies. They skim over mud as well as the water surface. They can catapult themselves for a distance of up to 60cm and actually move faster on land and on the water surface than by swimming with their bodies in water.

A distinctive and endearing feature of mudskippers is that their huge goggly eyes at the top of their heads. Unlike other fishes, mudskippers prefer to swim with their heads above water, thus giving them a good 360 degree view.

Corny Joke: Their eyes are like a CCTV in action.

Interesting Fact: Mudskippers can also tolerate high levels of toxic substances such as cyanide.

Too Much Information

Gold-spotted mudskipper (Periophthalmus chrysospilos) Family Gobiidae

They tend to move around in groups, often in amusing 'herds', nervously moving just out of your reach. Sometimes they move in a line, following what seems to be the leader.

To about 12cm. Gaily speckled with orange spots on the undersides. The male raises his bright orange-and-black dorsal fin to court females and intimidate rival males. It eats small crabs, prawns and insects.

Giant mudskipper (Periophthalmodon schlosseri) Family Gobiidae

To about 27cm long, it is the largest of our mudskippers. It has a black stripe along the side of its body.

It builds a pool in with deep tunnels in the mud as a nursery for its young. At low tide, they are often in or near their pool. At high tide, they might be seen clinging to mangrove tree roots.

An aggressive hunter, it eats mainly prawns, small crabs and insects. It may even snack on smaller mudskippers!

Yellow-spotted mudskippers (Periophthalmus walailake) Family Gobiidae

To about 13cm long, it has a greyish body with scattered yellowish spots. There are brownish spots on the upper body. The first dorsal fin is reddish with a broad black band and narrow white margin.

It was previously confused for the juveniles of the Giant mudskipper (Periophthalmodon schlosseri). Unlike the Giant mudskipper, the Yellow-spotted mudskipper does not have a broad black band along the body length.

It is said to be nocturnal, leaving its burrow at night to forage and returning to the burrow in the morning.

Assorted smaller mudskippers

We can't really be sure what they are, especially if they are viewed from the boardwalk. They could be juveniles of larger mudskippers or different species of small mudskippers.

Mudskippers are probably the only fish with movable eyelids!
To keep their eyes moist when they are on land, the eyes can be retracted to dip them into water that collects at the bottom of the eye socket. Their retinas have rod receptors above and cones below, giving them colour vision above and monochrome vision below!

They can absorb gaseous oxygen through blood-rich membranes at the back of the mouth and throat and they also absorb air through their skin which is rich with blood capillaries, so long as the skin remains moist.

Killer litter

'Line' of rubbish usually gathers at the back mangroves or on shores. This is the high water mark.

Thoughtful question: Let's see how many different kinds of rubbish we can see?

Where do you think this litter comes from?

When we DON'T throw litter into the bin, it falls to the floor, goes into the drain, flushes into the canal, then into the sea. Make sure all your litter goes into a proper dustbin.

Litter kills!

Strings and ropes: trap animals that die when the tide goes in or out. Fishes without water, dugongs drown in water.

Plastic bags: turtles mistake them for their favourite jellyfish food. Turtles will die if they swallow a plastic bag. Similarly for balloons, like the ones released during celebrations.

Plastic and styrofoam don't biodegrade. They stay in the ocean for a long long time, breaking down into smaller and smaller pieces. These are eaten by small animals and enter the food chain including our seafood.

For an article about the global impact of plastic in the ocean
Altered oceans: A plague of plastic chokes the seas
By Kenneth R. Weiss Los Angeles Times 2 Aug 06
or text version on wildsingapore

Links to more articles about marine litter on wildsingapore

You CAN make a difference

  • Throw all your rubbish in the dustbin.
  • Try to reduce the use of these things that you eventualy throw anyway: plastics, styrofoam, plastic bags.
  • Join International Coastal Cleanup Singapore. It's NOT just about removing rubbish. It is about collecting data about marine debris. The data is compiled worldwide and used to raise awareness and encourage change in consumer habits and government policy.
    See the ICCS results for 2006 7.5 tons of marine debris was collected from 11km of Singapore's shorelines in just one day.

Sunday, July 22, 2007

Mudlobster Condo

Mudlobster formations are found around the old prawn pond and inside the back mangroves (where the Nipah palms start getting abundant).
Three NAKED facts

Question: Can you guess what animal makes those funny volcano shapes in the mud?

naked fact#1: Without mudlobsters there will be fewer plants and animals in the mangroves.

Those volcanoes are the result of mudlobsters that dig deep in the soft mud. As they burrow about, mounds are created without them even knowing what happens above ground. Mudlobsters are seldom seen above ground.

The mound is like a cosy condo for all kinds of animals. These animals make little holes and tunnels to live in. These animals include crabs, ants, spiders, worms, clams, snakes, and shrimps.

Some plants also appear to grow better on these mounds.

Corny joke: The condo even comes with a swimming pool!

Water is trapped in the mound system forming pools which shelter fish and swimming animals at low tide.

naked fact #2: Mudlobsters are like earthworms. As they burrow and dig, they loosen the mud and allow air and oxygen-rich water to penetrate the otherwise oxygen-poor ground. This allows other animals and plants to make use of the mud.

naked fact #3: The Mudlobster is listed among the threatened animals in Singapore as their preferred habitats are lost or degraded. If it disappears, so will its 'condo' and the plants and animals living there.

Other interesting things to look for at mudlobster mounds

How many plants and animals can you see growing on the mound?

How can you tell whether the mound is an old one or one that is freshly made?

How high do you think a mudlobster mound can get? Records are 2m above the ground, which is taller than an adult human being! I've seen mounds at Lim Chu Kang that are as tall as me.

Too Much Information about Mudlobsters

This photo was taken of a mudlobster on Chek Jawa before deferment. It was spotted by Zeehan as we were having lunch on the big rock where the intertidal walks usually start! We don't know why it was wandering about in the open. We brought it to the prawn pond and left it there hoping it will burrow to safety.
Mudlobsters are not lobsters! Mudlobsters (Thalassina anomala) are more closely related to ghost shrimps of the genus Callianasa. A mudlobster can grow to about 30cm long.

What do they eat? No one knows for sure. They are believed to eat mud.

Can eat or not? There isn't really much of a mudlobster to eat. But they are eaten in some places. They are considered a nuisance by fish and prawn farmers as their digging activities undermine the bunds (raised edges of mud) that surround fish and prawn ponds.
Ubin villagers believed that mud lobsters can be eaten to treat asthma, but no scientific study has confirmed that.

Ferocious mud ant! There is a kind of ant that is found on mudlobster mounds that has a really nasty evil malignant bite. It's name is suitably Odontomachus malignus. I've been bitten by these tiny ants before, their bite really hurts! More about them on the Guide to the Mangroves of Singapore

Guide to the Mangroves of Singapore

No durians without mangroves?

Three NAKED facts

Question: How many of you like durians?

Question: What do you think pollinates the durian flowers?
If no one guesses right away. "I'll give you some clues: the durian flower looks like a pom-pom, it's white and it blooms at night" Eventually someone will guess bats.
naked fact #1: These bats only drink nectar and eat pollen. They don't eat fruits, they don't eat insects.

Question: "How often does the durian tree flower?"
Eventually they will realise once or twice a year. (We get durians year-round in Singapore because we import them from different places)

Question: "So what do these bats feed on when the durian is not in bloom?" If these bats relied only on durian flowers, they would starve to death.

naked fact #2: Mangrove trees like the Perepat (Sonneratia) have similar pom-pom-like flowers. Bats also feed on the nectar and pollen produced by these trees.
Such trees bloom more regularly and thus support a population of these bats. With more bats, more durians are likely to be pollinated.

naked fact #3: Without mangroves we may have fewer or even no durians!

Where to do this story? Preferably where the visitors can see a Perepat (Sonneratia) tree. As it is a long story, don't do it where it's hot, or mosquito-infested.

To ID a durian tree:
the long narrow leaves are dull green on the upperside and bronzy on the underside. The branches are somewhat angular and usually sparsely leafed.
Of course if there are durians on the tree, that's a dead giveaway!

Fruits trees of Chek Jawa

Rambutan (Nephelium lappaceum)
Among our favourite fruits, there are lots of rambutan trees throughout Pulau Ubin. And some on Chek Jawa too.

Jambu bol (Syzygium malaccense)
There are several of these large trees on the way to Chek Jawa and at Chek Jawa. The pom-pom like flowers are bright pink, and turn into oval shaped jambu. Apparently this jambu is very delicate and thus hard to bring to market. So you can only eat it at Pulau Ubin!

Coastal forest specials

Here are some showy and interesting plants that you might come across in the coastal forest of Chek Jawa.

False coffee plant (
Fagraea racemosa)
These tall bushy plants grow under the rubber trees in the coastal forest near Chek Jawa. Once in a while, they produce large white flowers that turn into bright green fruits.

Wild ixora (
Ixora congesta)
Called 'Jarum jarum' in Malay, which means 'bunch of needles'. Quite appropriate a name especially before the buds of the orange flowers open. These wild cousins of our garden ixora only bloom occasionally. But when they do, the dark gloomy floor is splashed with colour.

These vigorous climbing palms can be seen from the boardwalk. Their antennae-like tips poking out of the forest canopy. Rattans usually have lots of spines everywhere to help them clamber up trees to reach the sunlight. The spines on leaves often catch on forest trekkers' clothing. So the plant is sometimes also called the 'wait-a-minute' plant.

Rattans produce fruits encased in a scale-like covering. Some are edible.

Rare coastal forest trees of Chek Jawa

These trees of Chek Jawa's coastal forest are considered rare simply because most of Singapore's coastal forest habitats have already been cleared.

Nyatoh tree (
Pouteria linggensis)

Pong pong tree (
Cerbera odollam)
The Pong pong trees we see on growing our streets are from Malaysia. Our native Pong pong trees are very rare as most were wiped out as our coasts were developed. There are still a few native Pong pong trees on the shores of Chek Jawa, clinging onto the rocky cliffs.
Fruits are poisonous and often used as rat poison and for stupefying fish in small streams. Oil from seeds is rubbed on the body to treat cold, rheumatism and scabies. The latex is applied to sores and also as a remedy for stingray poison.

Delek air tree (Memecylon edule)
There are several of these rare and beautiful trees on the coastal hillside of Chek Jawa. The bluish purple flowers turn into red be

Sea shore nutmeg (
Knema globularia)
There are several of these trees in Chek Jawa's coastal forest. Hornbills love to eat the fruits.

Trees on the shores

Sea almond (Terminalia catappa)

Called 'Ketapang' in Malay, young small trees may be seen on the coast. The broad leaves may all turn red at the same time, giving the feeling of autumn on the shore.

The tiny white flowers turn into almond shaped fruits that are green when young and become brown and woody as they mature.

It is a common wayside tree in Singapore can be seen along Jalan Eunos/PIE going towards Changi and East Coast Park.

The leaves shed twice a year, usually from yellow to orange and to maroon colour and it finally drops off the tree but sometimes drop when it turned yellow. After the crown is bare, new leaves develop, after which the tree flowers. Fruits are also disperse by fruit bats and floats on the sea for days before reaching the shore and germinating.

Fruit has a thick husk and its kernel can be eaten taste which taste like almond. The timber can be used for building houses and boats. Fish hobbyist and some aquarium shops will usually soak these dried leaves into fish tank, especially for fighting fish because it produce tannin which believed to be good for their scales.

Alexandra laurel (Calophyllum inophyllum)

Called 'Penaga Laut' in Malay, this tall tree has beautiful white flowers that turn into round hard fruits. The broad shiny leaves have fine parallel veins.