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外形特征

行動(dong)遲緩，棲(qi)息于(yu)緩流的(de)淡(dan)水水體(ti)中，并不時上浮水面，吞入空氣，進行呼(hu)吸。體(ti)長(chang)(chang)，圓柱形(xing)，無鱗(lin)，灰褐色(se)，長(chang)(chang)可達(da)2.5公尺(chi)，重(zhong)可達(da)20千克。背鰭(qi)(qi)、尾(wei)鰭(qi)(qi)退化，但占(zhan)體(ti)全長(chang)(chang)近(jin)4/5的(de)尾(wei)，其(qi)下緣有一長(chang)(chang)形(xing)臀(tun)(tun)鰭(qi)(qi)，依靠臀(tun)(tun)鰭(qi)(qi)的(de)撥動(dong)而游動(dong)。尾(wei)部(bu)具發電器(qi)(qi)，來源于(yu)肌肉(rou)組(zu)織，并受脊神經支配。能隨意發出(chu)電壓(ya)高達(da)650伏特的(de)電壓(ya)。體(ti)表(biao)光(guang)滑無鱗(lin)，背部(bu)黑色(se)，腹(fu)部(bu)橙黃色(se)，沒有背鰭(qi)(qi)和腹(fu)鰭(qi)(qi)，臀(tun)(tun)鰭(qi)(qi)特別長(chang)(chang)，是(shi)主要的(de)游泳器(qi)(qi)官。有兩(liang)對形(xing)狀為長(chang)(chang)梭形(xing)的(de)發電器(qi)(qi)，位(wei)于(yu)尾(wei)部(bu)脊髓兩(liang)側(ce)。

電(dian)(dian)(dian)鰻尾(wei)部兩側的肌肉，是由有(you)(you)規則地(di)排列著的6000～10000枚肌肉薄(bo)片組(zu)成，薄(bo)片之間有(you)(you)結(jie)締組(zu)織相隔，并有(you)(you)許多神經直通(tong)中樞神經系(xi)統。每枚肌肉薄(bo)片像(xiang)一個(ge)小(xiao)電(dian)(dian)(dian)池(chi)，只能產(chan)生(sheng)150毫伏的電(dian)(dian)(dian)壓，但近萬個(ge)“小(xiao)電(dian)(dian)(dian)池(chi)”串聯起來(lai)，就可以產(chan)生(sheng)很高(gao)的電(dian)(dian)(dian)壓。

放電特性

放電的能力

電鰻發(fa)電是一(yi)種(zhong)(zhong)捕食(shi)和(he)打擊(ji)敵害的(de)手段，有時是一(yi)種(zhong)(zhong)生理需要(yao)。電鰻能(neng)隨意放電，自己掌握放電時間和(he)強度，發(fa)電器(qi)最主要(yao)的(de)樞紐是器(qi)官的(de)神經(jing)部分。

電(dian)(dian)(dian)鰻(man)(man)是(shi)魚類中放(fang)電(dian)(dian)(dian)能力最強的(de)(de)(de)淡水(shui)魚類，輸出的(de)(de)(de)電(dian)(dian)(dian)壓達300～800伏，因此(ci)電(dian)(dian)(dian)鰻(man)(man)有(you)水(shui)中“高壓線”之稱。電(dian)(dian)(dian)鰻(man)(man)的(de)(de)(de)發電(dian)(dian)(dian)器的(de)(de)(de)基本構造與電(dian)(dian)(dian)鰩相類似，也(ye)是(shi)由(you)許多電(dian)(dian)(dian)板組成的(de)(de)(de)。它(ta)的(de)(de)(de)發電(dian)(dian)(dian)器分布在(zai)身體兩側的(de)(de)(de)肌(ji)肉(rou)內，身體的(de)(de)(de)尾端為(wei)(wei)正(zheng)極(ji)，頭部(bu)為(wei)(wei)負極(ji)，電(dian)(dian)(dian)流(liu)是(shi)從尾部(bu)流(liu)向(xiang)頭部(bu)。當(dang)電(dian)(dian)(dian)鰻(man)(man)的(de)(de)(de)頭和(he)尾觸及敵體，或受到(dao)刺激影響時即(ji)可發生(sheng)強大的(de)(de)(de)電(dian)(dian)(dian)流(liu)。電(dian)(dian)(dian)鰻(man)(man)的(de)(de)(de)放(fang)電(dian)(dian)(dian)主要(yao)(yao)是(shi)出于生(sheng)存的(de)(de)(de)需要(yao)(yao)。因為(wei)(wei)電(dian)(dian)(dian)鰻(man)(man)要(yao)(yao)捕獲其他(ta)魚類和(he)水(shui)生(sheng)生(sheng)物(wu)(wu)，放(fang)電(dian)(dian)(dian)就是(shi)獲取獵物(wu)(wu)的(de)(de)(de)一種手段。它(ta)所釋放(fang)的(de)(de)(de)電(dian)(dian)(dian)量，能夠輕而易舉地把比它(ta)小(xiao)的(de)(de)(de)動物(wu)(wu)擊(ji)死(si)，有(you)時還會擊(ji)斃比它(ta)大的(de)(de)(de)動物(wu)(wu)，如正(zheng)在(zai)河里涉水(shui)的(de)(de)(de)馬和(he)游泳的(de)(de)(de)牛也(ye)會被電(dian)(dian)(dian)鰻(man)(man)擊(ji)昏。

電(dian)(dian)(dian)(dian)鰻放(fang)電(dian)(dian)(dian)(dian)時的(de)(de)平均電(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)350多伏(fu)，但(dan)也有過650伏(fu)的(de)(de)放(fang)電(dian)(dian)(dian)(dian)記錄。美(mei)洲電(dian)(dian)(dian)(dian)鰻的(de)(de)最(zui)大電(dian)(dian)(dian)(dian)壓(ya)竟達(da)800多伏(fu)，這么強的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)足(zu)以擊(ji)死一(yi)頭牛。電(dian)(dian)(dian)(dian)鰻放(fang)電(dian)(dian)(dian)(dian)時產生的(de)(de)電(dian)(dian)(dian)(dian)流是極微(wei)弱的(de)(de)，一(yi)般不到(dao)1安培(pei)(pei)；有時觀察到(dao)的(de)(de)電(dian)(dian)(dian)(dian)壓(ya)為(wei)(wei)500伏(fu)，電(dian)(dian)(dian)(dian)流為(wei)(wei)2安培(pei)(pei)，即(ji)功率為(wei)(wei)1000瓦(wa)的(de)(de)短時放(fang)電(dian)(dian)(dian)(dian)。雖然發出的(de)(de)是直(zhi)流電(dian)(dian)(dian)(dian)，但(dan)放(fang)電(dian)(dian)(dian)(dian)頻率每(mei)秒可達(da)300個脈沖。

放電的損傷力

放電(dian)(dian)(dian)的(de)(de)損(sun)傷(shang)力取決于鰻(man)魚的(de)(de)大(da)小和機體的(de)(de)狀況。當電(dian)(dian)(dian)鰻(man)長(chang)不到(dao)1米(mi)時，電(dian)(dian)(dian)壓隨著電(dian)(dian)(dian)鰻(man)的(de)(de)成長(chang)而增加。當長(chang)到(dao)1米(mi)后(hou)，只增加電(dian)(dian)(dian)流的(de)(de)強(qiang)度(du)。電(dian)(dian)(dian)鰻(man)每秒(miao)鐘(zhong)能(neng)(neng)放電(dian)(dian)(dian)50次(ci)，但(dan)連續放電(dian)(dian)(dian)后(hou)，電(dian)(dian)(dian)流逐(zhu)漸減弱，10～15秒(miao)鐘(zhong)后(hou)完(wan)全消失，休息一會(hui)后(hou)又能(neng)(neng)重(zhong)新(xin)恢復放電(dian)(dian)(dian)能(neng)(neng)力。在水(shui)(shui)中3～6米(mi)范圍內，常有人觸(chu)及電(dian)(dian)(dian)鰻(man)放出的(de)(de)電(dian)(dian)(dian)而被擊(ji)昏(hun)，甚至(zhi)因(yin)此跌(die)入水(shui)(shui)中而被淹死。

依靠電來感(gan)知(zhi)周(zhou)圍環境

電(dian)鰻(man)尾部(bu)發出的(de)(de)電(dian)流，流向頭部(bu)的(de)(de)感(gan)受器，因此在它(ta)身體周圍形(xing)成一(yi)個(ge)弱電(dian)場。電(dian)鰻(man)中樞神經(jing)(jing)系統中有(you)專門的(de)(de)細胞(bao)來監視電(dian)感(gan)受器的(de)(de)活動，并(bing)能根據(ju)監視分析的(de)(de)結果指(zhi)揮電(dian)鰻(man)的(de)(de)行(xing)為，決定采取捕食行(xing)為或避(bi)讓行(xing)為或其它(ta)行(xing)為。有(you)人曾經(jing)(jing)做(zuo)過這樣一(yi)個(ge)實驗：在水(shui)池中放(fang)置兩根垂直的(de)(de)導(dao)線，放(fang)入(ru)電(dian)鰻(man)，并(bing)將水(shui)池放(fang)在黑暗的(de)(de)環境里，結果發現電(dian)鰻(man)總在導(dao)線中間穿梭，一(yi)點兒也不會碰導(dao)線；當導(dao)線通電(dian)后(hou)，電(dian)鰻(man)迅速往(wang)后(hou)跑。這說明電(dian)鰻(man)是靠“電(dian)感(gan)”來判斷周圍環境的(de)(de)。

放電原理

電(dian)(dian)鰻(man)體(ti)(ti)內(nei)有一些細(xi)(xi)(xi)胞(bao)就像小型的疊層電(dian)(dian)池(chi)(chi)，當它被神經信號所(suo)激(ji)勵(li)時(shi)，能陡然使離子流(liu)通(tong)過它的細(xi)(xi)(xi)胞(bao)膜。電(dian)(dian)鰻(man)體(ti)(ti)內(nei)從(cong)頭(tou)到尾(wei)都有這(zhe)樣(yang)的細(xi)(xi)(xi)胞(bao)，就像許多(duo)疊在(zai)一起的疊層電(dian)(dian)池(chi)(chi)。當產(chan)(chan)生電(dian)(dian)流(liu)時(shi)，所(suo)有這(zhe)些電(dian)(dian)池(chi)(chi)（每個電(dian)(dian)池(chi)(chi)電(dian)(dian)壓(ya)約0.15伏）都串聯(lian)起來，這(zhe)樣(yang)在(zai)電(dian)(dian)鰻(man)的頭(tou)和尾(wei)之間就產(chan)(chan)生了很(hen)高的電(dian)(dian)壓(ya)。許多(duo)這(zhe)樣(yang)的電(dian)(dian)池(chi)(chi)組(zu)又并聯(lian)起來，這(zhe)樣(yang)就能在(zai)體(ti)(ti)外產(chan)(chan)生足(zu)夠大(da)的電(dian)(dian)流(liu)。用這(zhe)些電(dian)(dian)流(liu)足(zu)以將它的獵物或天敵擊(ji)暈或擊(ji)斃。淡(dan)水里的電(dian)(dian)魚需(xu)(xu)要更多(duo)的電(dian)(dian)池(chi)(chi)串聯(lian)在(zai)一起，因為淡(dan)水的電(dian)(dian)阻較(jiao)大(da)，產(chan)(chan)生同(tong)樣(yang)的電(dian)(dian)流(liu)需(xu)(xu)要更高的的電(dian)(dian)壓(ya)。

電鰻自身不被電的原因

電(dian)(dian)(dian)(dian)鰻的(de)放(fang)電(dian)(dian)(dian)(dian)器(qi)官在(zai)(zai)身(shen)(shen)體(ti)的(de)兩側，而(er)且它大部分(fen)的(de)身(shen)(shen)體(ti)或重(zhong)要的(de)器(qi)官都由絕緣(yuan)性很高的(de)構造包住(zhu)，在(zai)(zai)水(shui)(shui)中就像是一個大電(dian)(dian)(dian)(dian)池(chi)。電(dian)(dian)(dian)(dian)流(liu)由電(dian)(dian)(dian)(dian)阻最(zui)小的(de)通路經過，所以(yi)在(zai)(zai)水(shui)(shui)中放(fang)電(dian)(dian)(dian)(dian)時，電(dian)(dian)(dian)(dian)流(liu)會(hui)經由水(shui)(shui)（電(dian)(dian)(dian)(dian)阻比電(dian)(dian)(dian)(dian)鰻身(shen)(shen)體(ti)小）傳遞(di)，電(dian)(dian)(dian)(dian)鰻并(bing)不會(hui)電(dian)(dian)(dian)(dian)到(dao)自已(yi)。但如果電(dian)(dian)(dian)(dian)鰻被抓(zhua)到(dao)空(kong)氣(qi)中，因(yin)空(kong)氣(qi)的(de)電(dian)(dian)(dian)(dian)阻比它身(shen)(shen)體(ti)的(de)電(dian)(dian)(dian)(dian)阻更大，放(fang)電(dian)(dian)(dian)(dian)的(de)話(hua)就會(hui)電(dian)(dian)(dian)(dian)到(dao)自已(yi)了。另(ling)外(wai)，如果電(dian)(dian)(dian)(dian)鰻受傷(shang)使兩側的(de)絕緣(yuan)體(ti)同時破損的(de)話(hua)，放(fang)電(dian)(dian)(dian)(dian)時就會(hui)像兩條裸露的(de)電(dian)(dian)(dian)(dian)線一樣(yang)發生短路的(de)現象。

捕食特點

電(dian)(dian)(dian)鰻(man)捕(bu)食(shi)的時候(hou)，首先悄悄地(di)游(you)近魚群，然后可(ke)連續放(fang)出電(dian)(dian)(dian)流，受(shou)到電(dian)(dian)(dian)擊的魚馬上暈厥過(guo)(guo)去，身體(ti)僵直，于是(shi)，電(dian)(dian)(dian)鰻(man)乘機吞(tun)食(shi)它們。電(dian)(dian)(dian)鰻(man)放(fang)電(dian)(dian)(dian)，有時也不(bu)一(yi)定是(shi)為了捕(bu)食(shi)，也可(ke)能是(shi)一(yi)種(zhong)生理需要。被電(dian)(dian)(dian)鰻(man)電(dian)(dian)(dian)死的魚，往往超過(guo)(guo)它們食(shi)用所需要的量，這給漁業生產帶來危害。

南美(mei)洲土(tu)著居民利用(yong)電(dian)鰻(man)連續不斷(duan)地(di)放(fang)電(dian)后，需要經過(guo)一段時間(jian)休(xiu)息(xi)和補充豐富的食(shi)物后，才(cai)能(neng)恢復原有的放(fang)電(dian)強度的特(te)點，先將一群(qun)牛馬(ma)趕下河去，使電(dian)鰻(man)被激怒而不斷(duan)放(fang)電(dian)，待電(dian)鰻(man)放(fang)完(wan)電(dian)精(jing)疲力盡時，直接捕捉。

分布范圍

全(quan)世(shi)界(jie)的電(dian)鰻主要生長(chang)于熱帶及(ji)(ji)溫帶地區水域(yu)，除了歐洲電(dian)鰻及(ji)(ji)美(mei)洲電(dian)鰻分布在大(da)西(xi)洋外，其余均分布在印度洋及(ji)(ji)太平洋區域(yu)，南美(mei)洲亞馬孫河和圭亞那(nei)河、奧里諾科(ke)河流域(yu)也有分布。

生活環境

電(dian)鰻(man)(man)原產于海中，是一種(zhong)降河(he)性洄游魚類，溯河(he)到淡水內(nei)長(chang)大，電(dian)鰻(man)(man)在(zai)江河(he)湖泊中生長(chang)、發育，往(wang)(wang)往(wang)(wang)晝伏夜出，喜歡流(liu)水、弱光、穴(xue)居，具有(you)很(hen)(hen)強的溯水能力(li)，潛逃能力(li)很(hen)(hen)強。

生活習性

電(dian)鰻(man)常在夜間捕食，食物(wu)中有小魚、蟹、蝦、甲殼(ke)動(dong)物(wu)和(he)水生昆蟲，也食動(dong)物(wu)腐敗(bai)尸(shi)體(ti)，更(geng)有部分個(ge)體(ti)的(de)(de)食物(wu)中發現有高等(deng)植(zhi)物(wu)碎屑。電(dian)鰻(man)捕食的(de)(de)時候，首(shou)先悄悄地游(you)近魚群，然后可連(lian)續放(fang)出電(dian)流，受到電(dian)擊的(de)(de)魚馬上暈厥(jue)過去，身體(ti)僵直，于(yu)是電(dian)鰻(man)乘機吞(tun)食它(ta)們。電(dian)鰻(man)的(de)(de)攝食強度及生長(chang)速度隨水溫(wen)升高而增強，一般(ban)以春、夏兩季為最高。

放電能力

電(dian)(dian)(dian)(dian)(dian)鰻(man)雖名(ming)為(wei)“鰻(man)”，但并不是(shi)(shi)鰻(man)的(de)一種(zhong)，它在生物分類(lei)上和鯰魚更為(wei)接(jie)近，皆置(zhi)于(yu)骨鰾總目之下。電(dian)(dian)(dian)(dian)(dian)鰻(man)的(de)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)力(li)來自(zi)于(yu)它特化的(de)肌肉(rou)組織所構成的(de)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)體。肌肉(rou)組織幾乎都能(neng)(neng)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)，占其(qi)身長的(de)80%以(yi)上，有數以(yi)千計(ji)的(de)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)體。電(dian)(dian)(dian)(dian)(dian)鰻(man)的(de)頭部是(shi)(shi)負極，尾部是(shi)(shi)正極，每(mei)個(ge)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)體約可制造0.15伏(fu)特的(de)電(dian)(dian)(dian)(dian)(dian)壓，而當數千個(ge)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)體一起全力(li)放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)時(shi)的(de)電(dian)(dian)(dian)(dian)(dian)壓便高(gao)達600～800伏(fu)特，但這種(zhong)高(gao)電(dian)(dian)(dian)(dian)(dian)壓只能(neng)(neng)維(wei)持非常(chang)短(duan)暫的(de)時(shi)間，而且放(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)能(neng)(neng)力(li)會隨(sui)著疲勞或衰老的(de)程度而減退。電(dian)(dian)(dian)(dian)(dian)鰻(man)能(neng)(neng)自(zi)由控(kong)制要放(fang)(fang)(fang)出什么程度的(de)電(dian)(dian)(dian)(dian)(dian)力(li)，一般認(ren)為(wei)電(dian)(dian)(dian)(dian)(dian)鰻(man)放(fang)(fang)(fang)出低電(dian)(dian)(dian)(dian)(dian)力(li)的(de)目的(de)是(shi)(shi)在警(jing)告、試探(tan)或偵測。

電鰻(man)之所以能不被(bei)自(zi)己(ji)或(huo)同類電到，那(nei)是因(yin)為電鰻(man)體內(nei)的脂(zhi)肪(fang)組織有(you)很好的絕緣作用，而且電鰻(man)本(ben)身(shen)已很適應微弱的帶電環(huan)境。

一項最新的研究表(biao)明，電(dian)鰻(man)可以(yi)利用(yong)此電(dian)流(liu)對獵物(wu)進行“遠程控制”，使躲藏(zang)著的魚類(lei)抽搐(chu)從而暴露自己(ji)的位(wei)置。電(dian)鰻(man)的電(dian)流(liu)還會誘導獵物(wu)的肌肉不(bu)自主(zhu)地(di)收縮，從而使其癱瘓。美國田納西州范德(de)比爾特(te)大學(xue)生物(wu)學(xue)家肯尼(ni)斯·卡塔尼(ni)亞表(biao)示(shi)：“很明顯，電(dian)鰻(man)比人類(lei)更早(zao)發明泰瑟槍（發射帶電(dian)鏢箭使人暫時(shi)不(bu)能動(dong)彈的武器(qi)）。”

品種簡介

電鰻是整個魚(yu)類世界(jie)中最(zui)為人熟知的(de)物(wu)種之(zhi)一，它分布于亞(ya)馬遜流(liu)域的(de)圭亞(ya)那地區(qu)，雖然(ran)危險卻并不神秘，是當地有名的(de)傷(shang)人動物(wu)和餐桌美味。

外貌特征

電(dian)(dian)鰻(man)沒(mei)有(you)(you)背鰭(qi)(qi)，也沒(mei)有(you)(you)腹鰭(qi)(qi)，只有(you)(you)一(yi)對(dui)很(hen)小的(de)(de)(de)胸(xiong)鰭(qi)(qi)，和(he)跨越了(le)(le)整個(ge)下身的(de)(de)(de)超長(chang)(chang)臀鰭(qi)(qi)，一(yi)直(zhi)連(lian)接到尾鰭(qi)(qi)。電(dian)(dian)鰻(man)的(de)(de)(de)生存環境(jing)(jing)極其(qi)粗放，大多為渾濁、緩(huan)流的(de)(de)(de)水域，這(zhe)種(zhong)地(di)方給它(ta)帶來了(le)(le)兩個(ge)特(te)點(dian)：第(di)一(yi)是(shi)眼睛基(ji)本(ben)沒(mei)什么用了(le)(le)，很(hen)早就(jiu)退化了(le)(le)，必(bi)須依靠微弱的(de)(de)(de)電(dian)(dian)流探知周圍環境(jing)(jing)，所(suo)以電(dian)(dian)鰻(man)的(de)(de)(de)電(dian)(dian)路(lu)其(qi)實是(shi)長(chang)(chang)時開放的(de)(de)(de)；第(di)二就(jiu)是(shi)這(zhe)么臟的(de)(de)(de)水里肯定也長(chang)(chang)不出什么好看的(de)(de)(de)顏色(se)，所(suo)以電(dian)(dian)鰻(man)的(de)(de)(de)體色(se)十分一(yi)般，上體灰黑，下腹桔黃，是(shi)很(hen)通俗的(de)(de)(de)色(se)彩(cai)。

飼養方法

人(ren)工飼(si)養中(zhong)電(dian)鰻對(dui)水(shui)(shui)體更(geng)沒(mei)什么要求(qiu)，微(wei)酸至(zhi)(zhi)中(zhong)性水(shui)(shui)質，15℃以上(shang)的(de)水(shui)(shui)溫(wen)——這個溫(wen)度甚(shen)至(zhi)(zhi)冬天(tian)家里有暖氣的(de)話連加熱棒都(dou)(dou)不用放(fang)——然后過濾系統盡量提供緩動的(de)水(shui)(shui)流即可。電(dian)鰻還會直接呼吸(xi)空氣，連水(shui)(shui)體容氧(yang)的(de)問題都(dou)(dou)不必擔心。它們的(de)肛門雖然就(jiu)在胸(xiong)腹部下方，消化(hua)道極短，但還是(shi)挺(ting)能(neng)吃的(de)。并且由于它沒(mei)有牙齒，不能(neng)牢固咬住獵物(wu)，所以每電(dian)擊必至(zhi)(zhi)對(dui)方于死地(di)，投(tou)喂時務必小(xiao)心，不要自己把手放(fang)進水(shui)(shui)里。