There are at least 350 species of shark ranging from the smallest, the pygmy ribbontail catshark (8 to 10 inches long) to the largest, the whale shark (upto 45 feet long)
Sharks are equipped with a special set of sensors, arranged in clusters over their heads, that can pick up electromagnetic currents emitted from other animals. Sharks have bad eyesight, but these sensors help detect prey from 1 to 3 yards away. Sharks can also detect the electromagnetic fields of the Earth and may use this ability to guide them during migration.
Sharks are often thought of as cold-blooded killers that prey on humans. However, only 32 species have been known to attack humans, and most attacks are accidents. Often, sharks inhabit the same shallow, warm-water areas as humans. The shark may mistake a person standing or floating in water for natural prey. The shark goes in for the kill but, after one taste, usually gives up the attack.
Many shark attacks involve people trying to free sharks from fishing nets. Sharks also are territorial animals and may attack if they feel threatened. The chances of being attacked by a shark are very small, and the chances of dying from a shark attack have greatly decreased over the years. In fact, in the United States, a person is 30 times more likely to be killed by lightning than by a shark. Dog bites are 1,000 times more common than shark bites.
Sharks are fished for their fins and cartilage. Shark-fin soup is a popular food in some areas. After the fin is cut off, the rest of the shark is discarded. Shark cartilage is a subject of much scientific study because medicine made from it may stop the growth of tumors. Shark cartilage is sold in pill form as an alternative medicine. Shark finning and fishing for cartilage have caused a decline in populations in some areas of the world. Sharks mature and reproduce slowly, so it is difficult for them to rebound from a decline.
Great white shark: Best known from the movie Jaws, the great white is a large, heavy-bodied shark, about 20 feet long, with large bladelike teeth. Widely the most-feared of sharks, great white attacks are rare, and most scientists agree that its reputation is undeserved. Many scientists believe it is endangered due to sport fishing and shrinking food supplies.
Whale shark: Reaching lengths of up to 50 feet, the whale shark is the largest fish on earth. This gentle giant has small teeth like whale baleen, through which it strains small fish and crustaceans.
Tiger shark: The tiger shark is considered one of the most dangerous sharks. It is about 18 feet long and inhabits shallower water, often where people swim. The diet of tiger sharks varies widely and includes all types of sea life and even garbage.
Blue shark : The graceful blue shark is well known to scuba divers and commercial fishers - they have been seen circling divers and have followed fishing boats for days, eating stray fish.
Mako shark : Short-fin and long-fin makos are close cousins with the great white shark. They are very fast swimmers and can reach speeds of up to 60 miles per hour. Mako sharks can even leap out of the water.
Hammerhead shark : Hammerheads are best known for their distinctive mallet-shaped heads and widely spaced eyes, which they swing back and forth while swimming to detect prey. They are the only species of shark known to travel in schools.
Bull shark : The bull shark gets its name from its snout, which is wider than it is long. It is possibly more dangerous to humans than the great white shark because it lives in shallow, murky water in areas where people swim. The real shark attacks on which the movie and book Jaws were based were done by a bull shark.
鲨鱼属于脊椎动物门软骨纲(Chondrichthyes)板鳃亚纲,海生,少数种类进入淡水,为一群游速快的中大型海洋鱼类。
Sharks are vertebrates steel door cartilage (Chondrichthyes) elasmobranchii, Marine, a few species enter fresh water, as a group of large Marine fish speed is fast.
鲨内骨骼完全由软骨组成,常钙化,但无任何真骨头组织,外骨骼不很发达或退化,身体常被皮齿(质鳞),牙多样化,具有硬肌,但膜骨则永不存在,脑颅无缝。
Shark endoskeleton completely composed of cartilage, often calcified, but without any true bone tissue, degraded or exoskeletons is not very rich, the body is often skin teeth (scale), tooth diversification, with hard muscle, but never exist, membrane bone temple seamless.
上额由腭方软骨组成,下额由梅氏软骨组成。最新研究表明,鲨体内含有多种生物活性成分,如抗癌因子、角鲨烯、黏多糖等等。
On the forehead is composed of palatal side cartilage, the forehead is composed of Mr Medvedev cartilage.Sharks, according to new research in the body contains a variety of biological active ingredients, such as anti-cancer agent, squalene, mucopolysaccharides and so on.
扩展资料
鲨鱼的起源不详,但其地质学纪录可追溯到泥盆纪(4.08亿~3.6亿年前)。鲨鱼化石在中泥盆世出现,在石炭纪(3.6亿~2.86亿年前)成为占优势的脊椎动物。现代鲨鱼出现于侏罗纪早期(2.08亿~1.87亿年前),到白垩纪(1.44亿~6,640万年前)已经发展成现存的各科。
总之,除觅食和游泳机制的改进外,进化对鲨鱼的形态改变甚微。无论对化石种和现存种类来说,牙齿在鲨鱼种类鉴别方面均有很重要作用。
参考资料来源:百度百科-鲨鱼
鲨鱼的英语:shark
意思:
n. 鲨鱼
n. 贪婪的人;放高利贷的人;老手
v. 诈取;诈骗
词语搭配:
blue shark 大青鲨
cow shark 灰六鳃鲨(Hexan...
tiger shark 沙鲨
whale shark 鲸鲨
例句:The shark snapped its jaws shut.鲨鱼啪嗒一声把嘴合上了。
扩展资料:
近义词:steal
意思:
v. 偷;窃取
n. 偷窃;便宜货;(欺诈的)政治交易
语法:
v. (动词)
1、steal的基本意思是“偷”,指在未经允许或不为人知的情况下不正当地或非法地拿走本不属于自己的东西。用于比喻也可作“剽窃”解,引申指快速地、小心谨慎地做事情或是偷偷摸摸的、秘密的行为,着重强调手段和方式的隐秘性。steal还可引申表示“剥夺”“获取”“博得”解,多指用技巧取得。
2、steal可用作及物动词,也可用作不及物动词。用作及物动词时,接表示被偷物的名词或代词作宾语。steal也可接双宾语,其间接宾语可转化为介词for的宾语。
3、steal的过去式是stole,过去分词是stolen。
例句:He was sent into prison for stealing.他由于偷窃被送入监狱。
词汇搭配:
steal at 偷偷看某人一眼
steal from the house 溜出房子
steal from the rich 偷取富人的财物
steal into one's heart渐渐进入心里
鲨鱼用英语:shark ,读音:英 [ʃɑːk] 美 [ʃɑːrk]
n. 鲨鱼
n. 贪婪的人;放高利贷的人;老手
v. 诈取;诈骗
词汇搭配
1、bonito shark 灰鲭鲨
2、thresher shark 长尾鲨
3、blue shark 大青鲨
4、whale shark 鲸鲨
常见句型:
1、The shark is dangerous to swimmers.
鲨鱼对游泳的人来说很危险。
2、He told me he once caught a shark, but I know he was swinging the lead.
他告诉我有一回他捕到了一条鲨鱼,我知道他是在胡诌。
3、They were killed by a man-eating shark.
他们被一条吃人的鲨鱼所害。
扩展资料:
shark的同义词有:sharper、fraud , swindler
1、sharper英 ['ʃɑːpə] 美 ['ʃɑrpɚ]
释义:n. 骗子;赌棍;欺诈犯
例句:Her old sharper of a father did it.
她那骗子父亲干的好事。
2、fraud英 [frɔːd]美 [frɔːd]
n. 欺诈;骗子;伪劣品;冒牌货
[例句]She had committed fraud, embezzlement and theft.
她犯了诈骗、贪污和盗窃罪。
3、swindler英 ['swɪndlə]美 ['swɪndlɚ]
n. 骗子
[例句]Never shall I trust that swindler again.
我再也不会相信那个骗子了。
鲨鱼的英语是shark。
英 [ʃɑːk] 美 [ʃɑːrk]
n. 鲨鱼
n. 贪婪的人;放高利贷的人;老手
v. 诈取;诈骗
例句:The shark snapped its jaws shut.
翻译:鲨鱼啪嗒一声把嘴合上了。
短语:thresher shark 长尾鲨
近义词
cheat
英 [tʃiːt] 美 [tʃiːt]
vt. 欺骗;骗取
vi. 作弊;行骗
n. 骗子;欺骗
例句:We were on our honor not to cheat the customers.
翻译:我们以名誉担保不欺骗顾客。
短语:cheat sb's money 骗取某人的钱