LSM1303 Animal Behaviour Student Blog : dogface pufferfish

Is it a Water Balloon?! - Pufferfish

U0609533 — Fri, 21 Mar 2008 21:17:00 GMT

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 Puffer

A 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. This extremely strong, paralyzing poison is found in many parts of the pufferfish (including the liver, muscles, skin, and ovaries).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.

( Amazingly, the meat of some pufferfish is considered a delicacy. Called fugu in Japan, it is extremely expensive and only prepared by trained, licensed chefs who know that one bad cut means almost certain death for a customer. In fact, many such deaths occur annually.)

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! Like what the narrator in the video says: "how tough can it be (to catch the pufferfish for a meal)?? .... no matter what the otters tries, the puffer refuses to deflate itself...... it sets out to get a fish dinner, instead it is finding itself playing a ball game!"

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

Is it a Water Balloon?! - Pufferfish

U0609533 — Fri, 21 Mar 2008 13:18:00 GMT

An Inflated Spiny Puffer

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