The shark (systematic name Selachimorpha) is a crowd of elasmobranchii fish's generic term, this is a kind of ancient fingerling, when Jurassic Period already formed the modern type the shark, the shark body did not have the scale, the gill crack has 5 to 7.The different type shark has different food, some meat, may swallow the seal, the sea turtle even person, some only eats the plankton; The big body long amounts to 20 meters, small only then more than ten centimeters.Probably includes 5 item 20 branches (because classifies scientist's opinion not not consistently), distributes in the world each place temperate zone and the tropics sea, besides few sharks, if Greenland shark (Somniosus microcephalus), nearly not in frigid zone survival shark, because the common shark not too has the vigor in 20℃ following water temperature.
The shark all is penetrates the internal fertilization to reproduce, has the viviparity, the ovo-viviparity or the egg lives.
Shark's sense organ is quite keen, has the organ which induces to the electric wave, may detect hides under the sand game, even can smell several kilometer beside the rank smell of blood.
China ancient times called the shark is “jiao”, thought is only Yu the Long large-scale aquatic biology, in Shuowen does : “Fish.Has Le Langpan the country.From fish, Sha Shengsheng.」。
2008-05-06 20:36:35 補充:
The shark is injured cannot receive the bacterium infection, arouses many biologist's interests, the research extraction shark in vivo resist bacteria material, manufactures the new medicine.
http://student.bhps.tp.edu.tw/87069/Page10091/page100912.html
2008-05-06 20:36:39 補充:
Before the shark as early as appeared in the dinosaur for 300,000,000 years ago on already to have on the Earth, until now has surpassed for 400,000,000 years, they have not changed nearly in the recent 100,000,000 years.
2008-05-06 20:37:09 補充:
How many kind of sharks in the world has?
Approximately some 380 kind of sharks.Some 27 kinds can attack the humanity approximately, some 12 kind of possibilities can attack the humanity, but also some 27 kinds because of the build and the habitual relations, possibly have the risk.
2008-05-06 20:37:31 補充:
Shark's skeleton
All sharks all have body cartilage.Shark's skeleton is by the cartilage constitution, but is not constitutes by the bone.The cartilage is lighter than the bone, has the elasticity.All sharks all belong to the shark outline, but the shark outline animal all has the cartilage.
2008-05-06 20:38:04 補充:
What type build does the shark have?
Shark's build not one, height slightly to 6 inches, greatly to 18 meters.
The whale shark is in the sea the biggest fish, after grows into the height to be possible to amount to 60 feet.
2008-05-06 20:38:08 補充:
Although the whale shark's build is huge, its tooth in the shark is actually smallest.The smallest shark is the dwarf spiny dogfish, slightly enough to may place in the hand.It long approximately 6 to 8 inches, a weight also pound.
2008-05-06 20:38:35 補充:
* The world biggest fish is the whale shark.It may long amount to 18 meters, again amounts to 40000 kilograms.Their food is fortunately the plankton, otherwise, the humanity might have is difficult!
2008-05-06 20:39:01 補充:
The shark must forward swim unceasingly, otherwise can suffocate.
The shark must not stop the swimming, lets the water through the gill, otherwise can suffocate.
2008-05-06 20:39:05 補充:
The shark and the osteichthyes similarity is, they do not have the air bladder to control the diving.If the stop swimming, the majority of sharks can downward Shen.In order to reduce in the water the weight, in shark's liver has the massive oils.
2008-05-06 20:39:36 補充:
The shark except has humanity's five kind of sense organ, but also has other organs.
The shark keenest organ is a sense of smell, they can hear the number outside blood and so on the extremely slight material, and traces the origin.
2008-05-06 20:39:56 補充:
They also have the sixth sense----The electrification strength, the shark can the affiliation this kind of ability detection object all around several foot weak electric fields.
2008-05-06 20:40:01 補充:
They also may the affiliation mechanicalness feeling function, feel creates the vibration to 600 foot outside fish or the animal.
2008-05-06 20:40:30 補充:
In shark's life may give birth several thousand toeet.
* Shark's tooth *
Very many sharks including the big white shark, in the mouth all have Cheng Pai the favorable tooth.
2008-05-06 20:40:42 補充:
Because so long as the front-row tooth eats food to fall off, the rear tooth then can make up.The new tooth is greatly more durable than the old tooth.
2008-05-06 20:40:46 補充:
But sharks and so on spiny dogfish and thorn spiny dogfish can replace the entire platoon tooth.Shark's tooth assumes the zigzag, not only then, the shark can bite the game merely, also can effective their saw into pieces.
2008-05-06 20:41:04 補充:
Big white shark's on lower jaw by no means with forehead close connected.
Because big white shark's on lower jaw by no means with forehead close connected, it may upward and extends forward the upper jaw swallows down the game, sometimes even can swallow down game one.
2008-05-06 20:41:27 補充:
Becomes the shark staple food seal
The shark mostly as lives take the spoiled meat.
The shark is injured the sea mammalia, the fish and the spoiled meat for live, in rejection animal weak member.
2008-05-06 20:41:42 補充:
Under the shark also can eat the ship to upcast trash and other rejects.In addition, some sharks also can hunt each kind of sea mammalia, animals and so on fish and sea turtle and crab.Some sharks can several months not eat food, the big white shark is one kind.
2008-05-06 20:41:46 補充:
According to the report, the big white shark must separate for, two months only then eats food one time.