Sea Cucumber Excrement Could Save Coral Reefs

Sea Cucumber Excrement Could Save Coral Reefs

Oceans around the world have been acting like carbon sponges for billions of years.

Oceans suck in huge amount of carbon dioxide and thus maintaining the level of carbon dioxide in our atmosphere. They act link a sink or deposit box for carbon emissions. But the continuous rise of carbon dioxide level due to anthropogenic activities causes the oceans to become acidic. Yes-even with 4 feet of snow in Buffalo in recent weeks, HUMAN KIND IS ALTERING THE ENVIRONMENT.  

Low water pH is detrimental to coral reefs and aquatic lives, annihilating delicate reefs and fish eggs. This acidic water also effects the calcification of corals, their growth and ability to buffer our shores from storms and tidal influences.

There is one creature that could help save the reefs-- the humble sea cucumber.

Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number ofholothurian species worldwide is about 1,717. with the greatest number being in the Asia Pacific region. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter after which bacteria can continue the degradation process.

Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are usually reduced to isolated microscopic ossicles (or sclerietes) joined by connective tissue. In some species these can sometimes be enlarged to flattened plates, forming an armour. 

Image: animals.nationalgeographic.com

Image: seattletimes.nwsource.com

"When they ingest sand, the natural digestive processes in the sea cucumber's gut increases the pH levels of the water on the reef where they defecate," says One Tree Island deputy director, Professor Maria Byrne.

The excrement of this humble creature contains calcium carbonate (CaCO3), which is an essential component of coral.

"To survive, coral reefs must accumulate CaCO3at a rate greater than or equal to the CaCO3 that is eroded from the reef [by ocean acidification]," Maria says.

The waste also provides nutrients to assist coral growth.

One problem is the sea cucumbers are also threatened. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, bêche-de-mer or balate. If you ever saw an eviscerated sea cucumber you really have to wonder about the things people eat and like.....  But that is another entry. Given its role in coral conservation, we need to control sea cucumber harvesting to lessen the impact on reef health.

info: http://www.australiangeographic.com.au/journal/sea-cucumber-poo-could-save-great-barrier-reef-ocean-acidification-coral-one-tree-island.htm

Research Is A Dangerous Business

When people talk about risk at work, they normally mean the risk of getting laid off, terminated, losing a business deal, and probably encountering some minor accidents like electrocution while charging their electronics. 

Unlike these risks, the risks you encounter during research are far more unpredictable because you work with unpredictable subjects; the weather (climate scientists), wild animals (zoologists), chemicals (chemists), toxic jellies (marine biologists), unpredictable monkeys (lab scientists) and sometimes, the product of your own research - worm holes and such (physicists). Even in social sciences, the research is often far more dangerous than your average nine-to-five job.

Research isn't your typical 9-5 job.

Image: www.the-scientist.com

One particular technique in psychology, called participant observation, involves taking part in the activities of those you want to study. For example, if you wish to study the drug cartel, you would need to actually get your hands dirty. Sociologist Mick Bloor, a professor at the Cardiff School of Social Sciences once ended up in a bar fight while studying male prostitution in Glasgow. Lorraine Dowler from the Pennsylvania State University was forced to flee when her interviewee became the target of a street-level assassination attempt. Social scientist Frank Burton woke up one morning to find a submachine gun pointed at him. The body of Ken Pryce was found washed up on a Caribbean beach after investigating criminology in Jamaica.

These are just of the few workplace hazards that face researchers at work. We have yet to include stories of marine biologists who have face sharks and other dangerous marine predators, zoologists battling malaria, herpetologists getting bitten by snakes, and conservationists and medical scientists battling fanatic animal-rights activists. All very real possibilities in the modern world.

In April 2013, an animal-rights group that calls itself Fermare Green Hill (or Stop Green Hill) occupied an animal facility at the University of Milan, Italy, at the weekend, releasing mice and rabbits and mixing up cage labels to confuse experimental protocols. Certainly makes a strong case for microchip IDS and tattoos. Researchers at the university said that it will take years to recover their work. Michela Matteoli, a neurobiologist who works on autism and other disorders and lost most of her own research in the attack, says that she found some research students crying in the disrupted facility on Monday morning. Many of the animals at the facility were genetic models for psychiatric disorders such as autism and schizophrenia.

A study conducted in 1994 by Brian D Crandall and Peter W Stahl intended to investigate whether humans could digest bones. They trapped some shrews and after skinning and brief evisceration, they boiled one of the carcasses for approximately 2 minutes before swallowing it whole; head, limbs, body and tail. Without chewing. Talk about taking one for the team.

So it's very disrespectful for anyone to brush aside any researcher's project and label them as useless.

Research is not just for geeks. It's also for James Bond. 

Trematode: A Penis-Eating Parasite

There are many things in this world you do not want to encounter. For example the Candiru fish which lodges inside the urethra. Or perhaps something nasty like Ebola.  Some parasites live in the mouth - think Isopods in the mouth or tongue, or parasites in the intestines.

Today, I'm going to write about another parasite that eats not the tongue, but--get ready to cringe, guys--phallus.

Fortunately for us men these parasites prefer the penis of a type of sea snail called whelk.

A whelk. Image: http://en.wikipedia.org

Tremadotes are small parasitic flatworms that use molluscs as their intermediate hosts to reach their definitive host, the vertebrates. And once they end up in a molluscs, for instance a whelk, they will start chomping away the entire whelk gonad while waiting for a fish, for example an Atlantic cod, to devour the whelk. Thus passing along the life cycle to begin all over again.

In April 2000, a group of scientists from Canada decided to evaluate the impact of the parasites on the population of whelks in the northern gulf of St. Lawrence. The study--led by scientist Francoise Tetreault--involved collecting and dissecting 600 whelks and looking at their gonads, and compared the size of their gonads with the distribution of parasites.

The researchers discovered that there were 23% female and 15% male whelk whose gonads were affected. The parasite infected the digestive system as well, but 97% of the infected whelks had their gonads covered by 90% of the parasite.The parasite munched away a large portion of the male penis and changed the once bright color of the female gonad into pale grey.

Picture (B) shows an uninfected whelk. Its penis is labelled as "P".
Picture (D) shows an infected whelk. Look at the "P", and the whelk's sad face.
Awwww.... 

Picture (A) shows the gonad(G) and digestive system(DG) of a female whelk.
Pciture (B) shows the pale grey gonad of an infected female whelk.

Luckily for us there is no parasite that loves eating human penis, just living inside for a while. As for the whelks, they can only watch helplessly as the trematode feasts on their manhood.
Sucks to be a male whelk.But also goes to show you there is always something bigger in the ocean to eat you, and if its not bigger, then its smaller and will still eat you.

Why Do Bees Build Hexagonal Cells?

Have you ever wondered why bees build hexagon-shaped cells?

I have some odd things that keep me up late at night.  This is one of them.  In researching bee-keeping (an item on my bucket list) I keep going back to one simple question. Why do bees make hexagonal shaped cells? Isn't it fascinating? Why hexagon? Why not other shapes? Why not triangles or octagons? And these apparently simple, instinct-driven creatures could build the perfect-six-sided-hexagon which, when you stack them up together, form a perfect array of honeycomb.

Image: www.bee-hexagon.net

More than 2000 years ago, Marcus Terentius Varro proposed an answer to this question. He thought maybe honeycomb built of hexagons can hold more honey and require less building wax, and this answer has since been called "The Honeybee Conjecture".

Supporting this hypothesis is that first up, we all know that honeycombs store honey. Honey is what sustains the entire colony, so obviously it's very precious. A typical colony consists of 100,000 individuals, so you need a lot of honey to keep them alive. To store that much honey, you'll need a warehouse big enough to store them, but small enough to prevent thieves like the Japanese Giant Hornets (as long as your thumb), bears and other creatures from breaking in. In fact a single cell is just big enough to let a single worker pass through.

The Japanese Giant Hornet is at least five times larger than the honey bee. Image: waynesword.palomar.edu

So you need to start with a shape. Shapes like circle, pentagon, heptagon and octagon are bad shapes because you can't stack them up together without leaving gaps. And when you're talking about building a place to store as much honey as possible, every gap is considered a waste of space.

So that leaves us with triangle, square and hexagon. Out of these three, why hexagon?
It turns out that hexagon uses the least wax to produce compared to triangle and square of the same cross-sectional area.

To produce a square with area, A=100cm2, the circumference is 40.0 cm.

To produce a triangle with area, A=100cm2, the circumference is 45.588 cm.

To produce a hexagon with area, A=100cm2, the circumference is only 37.224 cm.

Ironically, the one with the least number of sides (triangle) is the one that requires the most wax to build.

This means that by building hexagon-shaped cells, the bees can reduce the usage of wax, which is also made from honey (now that makes sense).

Now one could think there are a lot of calculus loving bees out there engineering perfect hives.  But if we revisit our friend Darwin, we can easily see how less effort, plus more energy equaled a more successful hive and thus the genes for geometry learned bees get passed along.

Now that i've got the hexagonal hive business all sorted out, I need another problem to ponder late at night.

Research Is A Dangerous Business for Some

When people talk about risk at work, they normally mean the risk of getting fired, getting hit by a bus, and probably encountering some minor accidents like electrocution while charging their electronics. 

Unlike these risks, the risks you encounter during research are far more unpredictable because you work with unpredictable subjects; the weather (climate scientists), wild animals (zoologists), chemicals (chemists), and sometimes, the product of your own research (physicists). Even in social sciences, the research is often far more dangerous than your average nine-to-five job.

One particular technique in behavioral psychology, called participant observation, involves taking part in the activities of those you want to study. For example, if you wish to study the drug cartel, you would need to actually get your hands dirty. Sociologist Mick Bloor, a professor at the Cardiff School of Social Sciences once ended up in a bar fight while studying male prostitution in Glasgow. Lorraine Dowler from the Pennsylvania State University was forced to flee when her interviewee became the target of a street-level assassination attempt. Social scientist Frank Burton woke up one morning to find a submachine gun pointed at him. The body of Ken Pryce was found washed up on a Caribbean beach after investigating criminology in Jamaica.

These are just of the few workplace hazards that face researchers at work. We have yet to include stories of marine biologists who have face sharks and other dangerous marine predators, zoologists battling malaria, herpetologists getting bitten by snakes, and conservationists and medical scientists battling fanatic animal-rights activists.

Image: www.the-scientist.com

In April 2013, an animal-rights group that calls itself Fermare Green Hill (or Stop Green Hill) occupied an animal facility at the University of Milan, Italy, at the weekend, releasing mice and rabbits and mixing up cage labels to confuse experimental protocols. Researchers at the university said that it will take years to recover their work. Michela Matteoli, a neurobiologist who works on autism and other disorders and lost most of her own research in the attack, says that she found some research students crying in the disrupted facility on Monday morning. Many of the animals at the facility were genetic models for psychiatric disorders such as autism and schizophrenia.

A study conducted in 1994 by Brian D Crandall and Peter W Stahl intended to investigate whether humans could digest bones. They trapped some shrews and after skinning and brief evisceration, they boiled one of the carcasses for approximately 2 minutes before swallowing it whole; head, limbs, body and tail. Without chewing.

So it's very disrespectful for anyone to brush aside any researcher's project and label them as useless.

Research is not just for geeks. It's also for James Bond. 

How The Zebra Got Its Stripes?

So the other day I was driving my kids around and they asked how did the zebra gets its stripes.

The explanation I saw from documentaries stated that zebra evolved its stripes to confuse the lion.

Lions are color blind,as are many cats,  so a group of rampaging zebras can be extremely confusing and headache-inducing. With the tall African savannah grasses, one can easily see that the stripes, combined with the tall grasses could easily break up the lines of a zebra and be confusing to predators.  Sounds right, so I figured that wrapped up that little science lesson.  But I got home and did some research on the subject.

I found an entirely plausible other reason for the strips. Gabor Horvath and colleagues from Hungary and Sweden have come up with another explanation: zebra's stripes ward off blood-sucking parasites.

Image: animals.howstuffworks.com

Like us, animals hate parasites too, and one parasite, the female horseflies (tanabids) can deliver one hell of a bite. Like female mosquitoes, they feed on mammal blood for reproduction, and they carry diseases too.Locally mosquitos transmit the dinofilaria (Heartworm) parasite to dogs and cats, so it makes sense from an evolutionary viewpoint to develop a natural "Frontline" so to speak.

Image: en.wikipedia.org

They lay their eggs on stones or vegetation close to water, guided by the horizontally polarized light reflected from the water surface. And these evil vampires are also guided to their meals via horizontally polarized light reflected from animal skin.

Image: whatis.techtarget.com

To test this, the team traveled to a horsefly-infested farm in Budapest and set up three horse model; a white, a dark, and a striped model. Interestingly, the striped model was the least attractive to horseflies. The team also varied the width, density, and angle of the stripes, and found out that narrower stripes attracted fewer tanabids.

The team pointed out that developing zebra embryos start out with a dark skin, only to develop white stripes afterwards. It's possible that evolution has favored the development of zebra stripes to confuse color-blind predators, as well as ward off blood-thirsty vampires.

Should we do the same to ward off mosquitoes? Who knows, perhaps I will develop a line of striped clothing for hikers and make a fortune warding off blood sucking insects. At the very least it may save you from a Lion attack.


info: 
Polarotactic tabanids find striped patterns with brightness and/or polarization modulation least attractive: an advantage of zebra stripes, Ádám Egri et. al, J Exp Biol 215,  March 1, 2012  736-745. 

Evolution of the Whale

Evolution of the Whale

The Blue Whale is the largest living creature on the planet.  It is hard to believe it evolved from  a land mammal roughly the size of a dog. While this is accepted as science fact, I have had many a discussion with those unwilling to believe this. But who cares~ no one believed in Max Planck in the first place, not even himself, and everyone was laughing at Charles Darwin when he suggested that we are closely related to macaques.

The cetaceans (whales, dolphins and porpoises) are marine mammal descendants of land mammals. Their terrestrial origins are indicated by:

• Their need to breathe air from the surface;
• The bones of their fins, which resemble the limbs of land mammals
• The vertical movement of their spines, characteristic more of a running mammal than of the horizontal movement of fish.

The question of how a group of land mammals became adapted to aquatic life was a mystery until discoveries starting in the late 1970s in Pakistan revealed several stages in the transition of cetaceans from land to sea.

This animal existed 50 million years ago by the rivers of southern Asia, walking on slender legs tipped with hooves, and takes to the water whenever it senses danger

It is called Indohyus (meaning India's pig)

and it is the earliest known relatives of today's whales and dolphins.

According to molecular evidence, the closest living relatives of whales are, quite surprisingly, the artiodactyls, a group of hoofed mammals that includes deer, cows, sheep, pigs, giraffes, camels and hippos, yet not a single one of them bears even a passing resemblance to whales and dolphins. Among the group, the hippos are evolutionarily closest and while they are at least at home in water, their family originated some 35 million years after the first whales and dolphins did.

Even though Indohyus had the elegant legs of a small deer and walked around on hooves, it also had features found only in modern and fossil whales.

It's jaws and teeth were similar to those of early whales, but the best evidence was the presence of a thickened knob of bone in its middle ear (involucrum). This structure helps modern whales to hear underwater, it’s only found in whales and their ancestors, and acts as a diagnostic feature for the group.

We should, however note that this animal IS NOT the direct ancestor of whales, it is only a sister group to the ancestors of whales. Got it?

So why did they go aquatic? Scientists speculate that whales developed from an Indohyus-like ancestor that fed on plants and possibly small invertebrates on land, but fled to water to escape predators. Over time, they slowly turned into meat-eaters and evolved to swim after nimble aquatic prey.

For a much more in-depth comparison see http://en.wikipedia.org/wiki/Evolution_of_cetaceans

Info gleaned from http://blogs.discovermagazine.com/notrocketscience

People Who Doodle Learn Faster

New research published recently shows that doodling helps you learn. In fact, say scientists, students should be encouraged to doodle while they take notes in class.

"A doodle is an unfocused drawing made while a person's attention is otherwise occupied. Doodles are simple drawings that can have concrete representational meaning or may just be abstract shapes."

Our first encounter with doodling often begins at an early age, and most often with crayons.  Some scribbles on a page. But it is a great time to explore how colors combine, the cause and effect of drawing outside the lines, and some basic hand eye coordination. 

As we age we are able to draw better.  Simple copying becomes common place.  Hand sketches and creative drawings soon follow.  If you have caught the doodle bug then you will find yourself doodling in the margins of your notes, papers, and even books.

I recently did some spring cleaning and found a bunch of old notebooks from school.  I had a rather large quantity of doodles in my margins.  This of course tells me a few things. I was bored and I like to keep my mind, or at least hands busy, especially when bored.

Some grouos of people tend to doodle more than others, at least in my experience. I noticed that physicists doodle a lot; movement of planets, objects, propagation of light, etc. My notes are littered with funny diagrams, phrases and questions so it would be hilarious if it somehow got into someone else's possession.

Image: exampaper.com.sg

Another group that doodles alot are naturalists.  The study of live and animals and plants often requires a basic understanding of how they work and look.  Doodling can help a budding scientist begin to learn these things.

The thing is, our brain loves diagrams, or any funny and entertaining jokes, stories. So by doodling (about the topic at hand, mind you),  you can engage people who might otherwise not pay attention; it helps them learn how information is presented; it inspires learning and retention of information; and it can assist people in communicating that information later.

So, go ahead and draw in the margins. It's helping you get the most out of that boring meeting — science says so!

Animal Mimicry-- The Art of Deception

Mimicry is an art.

Human seeks to mimic animal call, other humans, a certain repertoire for the purpose of hunting, defence, or simply to entertain. But even a seasoned mimicry artist of our world would have paled in comparison to some of the masters of mimicry of the animal kingdom.

For them, mastering the art of mimicry is a matter of life or death.

A Stick Insect. Image:http://en.wikipedia.org/wiki/Phasmatodea

Most animals mimic to defend themselves. Some to attract mate, and some, for example chameleons
and alligator snapping turtles mimic(or camouflage) for food.

An Alligator Snapping Turtle. Image: www.itsnature.org

Yesterday I read this article about a phorid fly, Vestigipoda longiseta, from southeast Asia, that mimics ant larvae.

Image:http://whyevolutionistrue.wordpress.com/2010/09/24/adult-fly-mimics-ant-larva/

The long “grubworm” part of the body is simply the enormously elongated and unpigmented abdomen of the adult. This has all evolved from an ancestor that looks pretty much like the flies you know.

You can imagine why natural selection would favor this resemblance: the ants tend and feed the larvae, and mistake the flies for their own brood. It’s a lifetime of free lunches! The ants also protect the flies and carry them (like they carry their own larvae) when a colony is on the move.

An adult of V. longiseta being carefully carried by an Aenictus ant. Image: http://whyevolutionistrue.wordpress.com/2010/09/24/adult-fly-mimics-ant-larva/

Why can’t the ants detect these intruders? Well, they’re not terribly harmful, getting just a bit of food from the colony, so there’s probably not strong selection to weed them out. Ants, of course, have pretty bad vision, so they probably can’t see the intruders as different from their own brood. There’s probably chemical mimicry going on here as well: the hydrocarbon molecules on the fly’s cuticule may well resemble the compounds on ant larvae, so that the ants, who “taste” these hydrocarbons, are fooled by chemical mimicry.

Another master of mimicry that I would like to introduce to you all is the Mimic Octopus. Read my previous post~

A Mimic Octopus. Image: zmescience.com

And another one which really amazes me is the Superb Lyrebird. I remember watching a video about the mimicry power of this bird when I was in Form 2, and I thought it was fake. Given the handicapped technology of that time, and the level of maturity of the audience, I was unable to record the episode for further review.

A Superb Lyrebird. Image:cae2k.com

Nevertheless, I found this video on youtube yesterday. Watch as Sir David Attenborough (Sir David Attenborough is a fantastic naturalist; down-to-earth, full of knowledge, a titan of science) relates the ability of this bird to mimic the call of every other birds, including other sounds it hears: chainsaw, camera shutter, cars... FOR REAL!

A planthopper mimicking a leaf. Image:http://en.wikipedia.org/wiki/File:Mimicry_of_Siphanta_acuta_edit1.jpg

Image:falkenblog.blogspot.com

Image:http://conservationreport.com/2008/11/08/

Caterpillar mimicking a snake to scare off birds. Image: www.amnh.org

Dead-leaf butterfly. Image:http://conservationreport.com/2008/11/08/

How Mosquitoes Fly In The Rain

Have you ever wondered how insects, especially small ones like mosquitoes and flies survive the downpour?

Raindrops pose hazard to mosquitoes because of their relatively large mass and speed. A mosquito is around 2~5mm in length, weighs around 2mg, and flies at 1m/s. On the other end, a drop of rain has 1~4mm radius, weighs 2~50 times the weight of a mosquito, and travels at 5~9m/s. Putting that into perspective, it's like us getting hit by a blob of water with the size of a shopping cart, weighs 3 tons and travels at 18~32 km per hour.

It's an irony that the delicate blood-sucking parasite thrives in wet, rain-laden tropical country like Malaysia. Wouldn't they be crushed to death by the raindrops?

Image: en.wikipedia.org

Mechanical engineer David Hu of the Georgia Institute of Technology who thought of this question placed some mosquitoes in a cage and exposed them to water drops. Slow motion footage showed that rather than dodging the water drops, the insect flew right into the them.

Since the mosquitoes were so lightweight, the raindrops lost very little momentum upon impact. By minimizing resistance, the insect minimized the impact of collision. So instead of flattening the insect, the water drops simply spun the mosquitoes away, though the insects recovered soon afterward.
It's like an asteroid hitting a piece of paper: the paper is so lightweight that it's just pushed aside.

And nature has given mosquitoes a helping hand: mosquitoes are designed to be hydrophobic, thanks to the hairs on the mosquitoes' body. The hairy surface increases the wing's surface area, and thus its energetic cost of wetting. Thanks to this hydrophobicity, low speed drops simply bounce off the insect.

Image: rationaldiscoveryblog.com

Moreover, insects are blessed with hard exoskeleton to help them withstand the impact. And mosquitoes could withstand sudden acceleration of up to 300Gs. If we were in a comparable situation we wouldn't even survive past 2Gs.

Thanks to its tiny weight and hydrophobicity, the evil parasite lives to suck another victim.



info:
http://www.youtube.com/watch?v=XWyoy44oV3Q
http://discovermagazine.com/2012/mar/31-how-mosquitoes-survive-in-a-downpour
http://inkfish.fieldofscience.com/2012/06/why-you-cant-kill-mosquito-with.html

Pufferfish toxin

The Pufferfish is considered the second deadliest vertebrate in the world, after the Golden Poison Frog. The common image we have of this creature is that it inflates when threatened. I have kept these fish in an aquarium, and in my experience they rarely puff out in captivity.

What makes the Pufferfish, also called the Fugu so popular is the lethal toxin in its liver, skin and the ovaries, and the fact that the Japanese treat it as a delicacy. Pretty ironic I guess? By the way it is extremely expensive and prepared only by trained, licensed chefs who, like all humans, occasionally make mistakes.

Image: blogs.bootsnall.com

Almost all pufferfish contain tetrodotoxin, a substance that makes them foul tasting and often lethal to fish. To humans, tetrodotoxin is deadly, up to 1,200 times more poisonous than cyanide. The toxin paralyzes the muscles, including the muscles in our diaphragm, which is essential for breathing. The victim eventually dies of asphyxiation. There is enough toxin in one pufferfish to kill 30 adult humans, and there is no known antidote. Tetrodotoxin has been isolated from widely differing animal species, including western newts of the genus Taricha (where it was formerly termed "tarichatoxin"), pufferfish, toads of the genus Atelopus, several species of blue-ringed octopuses of the genusHapalochlaena (where it was called "maculotoxin"), several sea stars, certain angelfish, a polyclad flatworm, several species of Chaetognatha (arrow worms), several nemerteans (ribbonworms) and several species of xanthid crabs.

Tetrodotoxin molecule

Image: gastroville.com

Negative aspects aside, Puffer Fish makes cute companion.

Of course, don't go around scaring puffer fish because a puffer fish could only perform a limited number of inflation in its life.

Image: animals.nationalgeographic.com

When a Pufferfish is threatened, it will pump itself up by taking 35 gulps or so in the course of 14 seconds. Each gulp draws in a big load of water thanks to some peculiar anatomic changes in the muscles and bones. The entire fish balloons as it continuously takes water into its stomach.

The stomach expands to nearly a hundred times its original volume, and the fish's spine, already slightly curved, bends into an upside-down U shape, and all other internal organs become squeezed between the fish's backbone and its rapidly expanding stomach. Meanwhile, the fish's skin is pushed out, obscuring most of the puffer's features-http://divingintaganga.blogspot.com/2010/09/how-and-why-pufferfish-inflate.html

Image: Sally J. Bensusen. American Museum of Natural History.

Sometimes they have difficulties expelling water from their stomach, and hence they actually risk dying every time they inflate. I guess we should record a default video showing one individual inflating itself on a public website to prevent curious divers/swimmers/fishers going around harming more Pufferfish. Pufferfish belong to family Tetraodontidae is a family of primarily marine and estuarine fish of the order Tetraodontiformes. The family includes many familiar species, which are variously called pufferfish, puffers, balloonfish, blowfish, bubblefish, globefish, swellfish, toadfish, toadies,honey toads, sugar toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines (unlike the thinner, hidden spines of Tetraodontidae, which are only visible when the fish has puffed up). The scientific name refers to the four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey.

With all of this, many people still consider Fugo to be a delicacy , especially in Japan.


info:
http://www.aquaticcommunity.com/predatory/pufferfish.php
http://en.wikipedia.org/wiki/Fugu
http://divingintaganga.blogspot.com/2010/09/how-and-why-pufferfish-inflate.html