The Water Balloon = Pufferfish...When we think about pufferfish, we would normally associate it with its ability to puff itself up and make itself look really bloated and big. But have you ever wondered how it actually happens? Get to know some of the facts, find out some other interesting behaviours and witness for yourself how the pufferfish defends itself from its predator by inflating itself up!
Introduction:The pufferfish, also called blowfish, swellfish, globefish and balloonfish, make up the family
Tetraodontidae, in the order
Tetraodontiformes.
They are named for their ability to inflate themselves to several times
their normal size by swallowing water or air when threatened. The
scientific name,
Tetraodon, refers to the fact that they have
four large teeth, fused into an upper and lower plate, which are used
for crushing the shells of crustaceans and mollusks, their natural prey.
Puffed up pride: The pufferfish's unique and
distinctive natural defenses are necessary due to its slow speed.
Pufferfish use a combination of pectoral, dorsal, anal, and caudal fins
for propulsion, making it unmaneuverable and an easy target for
predators. As a defense mechanism, pufferfish have the ability to
inflate rapidly, filling their extremely elastic stomachs with water
(or air when outside the water) until they are almost spherical in
shape. They turn themselves into a virtually inedible ball several
times their normal size. Thus, a hungry predator stalking the pufferfish may suddenly
find itself facing what seems to be a much larger fish and pause,
giving the pufferfish an opportunity to retreat to safety.
One particular pufferfish, spiny puffer (
Diodon holocanthus) combines
inflation and pointy spikes in one spectacular defense mechanism. Compared with creatures like these, the spiny puffer seems relatively
normal when relaxed. But when threatened, the puffer undergoes a remarkable
transformation, its body swelling until the fish is three times its
usual size and has become a rigid, near-perfect sphere covered in spiky
armor-not a good design for swimming but decidedly discouraging to attackers.
An Uninflated Spiny PufferA more accurate
name for this fish would be "pumper," because it inflates not by puffing
itself up but by pumping water into its stomach (which has ceded its
digestive function entirely to the intestine). The stomach expands to
nearly a hundred times its original volume, an astonishing increase
made possible by the stomach's being pleated, like a skirt. An amazing
amount of material can be hidden away in pleats.
As the puffer fills with water, the fish's spine, already slightly
curved, bends into an upside-down U shape, and the liver, intestines,
and 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. Only the mouth-a cartoonish orifice containing heavy, crushing
plates capable of pinching a human finger to the bone-remains unaffected.The skin of a fully inflated puffer is stretched to one and a half
times its resting length.
"As a
spiny puffer pumps water into its stomach, the stomach
inflates and the spine arches to accommodate the organ's
expansion. Pockets of the stomach soon get shoved above
and around the spine, making the fish nearly spherical."
An Inflated Spiny Puffer
The skin also helps deploy the puffer's armor. The scales of this fish
have been modified into slender spikes, each on a tripod-shaped, bony
base embedded in the skin. Normally the tripod lies on its side, with
the spike flat against the skin, pointing backward. But when the fish
puffs up, the stretched skin pulls two of the tripod's legs backward
and one leg forward, snapping the spike upright. The three legs provide
a secure base that blunts the force of anything pushing against the
spike's sharp tip.
Last Line of Defense:A predator that manages to snag a puffer before it inflates won’t feel
lucky for long. 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.
There is enough toxin in one pufferfish to kill 30 adult humans, and
there is no known antidote.
Other Interesting Behaviour:
Another type of pufferfish, Dogface Puffer, Arothron nigropunctatus, is renowned to have a charming personality, and it is a very individualistic fish. Some interesting facts has been observed when it is kept in captivity. It is reported that when a Black Dogface Puffer is young, it should only be kept with
docile and non-aggressive species, since a young Black Dogface Puffer
fish is easily frightened. If a young Black Dogface Puffer feels
insecure or harassed in the aquarium it might refrain from eating and
begin to starve. A Black Dogface Puffer can also loose its appetite if it feels stressed
in the aquarium. Unsuitable aquarium companions can stress the Black
Dogface Puffer fish tremendously, e.g. poor water quality and tiny space with no place to seek shelter.
What is so Interesting about that?!
If these boring facts are boring you, then how about watching this video? This would probably make you think: 'WOW! PUFFERFISH ARE SO COOL!' Their nature of defence against predators is indeed intriguing and amusing!
References:
"
Pufferfish, Blowfish, Fugu or Globefish" by Enchantedlearning.com, 21 March 2008
"Tetraodontidae" by Wikipedia, 21 March 2008
"
A Fish Story" by
Adam Summers (Illustrations
by Sally J. Bensusen) by American Museum of Natural History Biomechanics, 21 March 2008
"Pufferfish" by Sheppard Software, 21 March 2008
"Pufferfish" by National Geographic, 21 March 2008
"Freaks of Nature: Self Inflating Fish" by National Geographic, 21 March 2008
"Black Dogface Pufferfish" by Aquatic Community, 21 March 2008
"Arothron Dog Face Puffer" by Tropicalfishdata.com, 21 March 2008