Ngaphambi kokuthola ukuthi oshaka balale kanjani, udinga ukuthola ukuthi, empeleni, lezi zilwane zasolwandle (ezimelwe yizinhlobo ezingama-450) ziyawazi umqondo onjengokulala.
Ngabe oshaka balele noma cha?
Ukulala kahle (okufana nokwabantu) akuyona into ejwayelekile koshaka. Kukholakala ukuthi noma yimuphi ushaka akazivumeli ukuthi aphumule imizuzu engaphezu kwengu-60, ngaphandle kwalokho usongelwa ukuminyana.... Lapho intanta, amanzi ayizungeza futhi ayiwashe imithambo, esekela umsebenzi wokuphefumula.
Kuyathakazelisa! Ukulala ngejubane eligcwele kugcwele ukumisa ukuphefumula noma ukuwela phansi, kulandelwe ukufa: ekujuleni okukhulu, inhlanzi eleleyo izomane icofwe ingcindezi.
Ukulala kwalezi zinhlanzi zasendulo ezinenqwaba (ezihlala eMhlabeni iminyaka engaphezu kwezigidi ezingama-450) kungabangelwa ukumiswa okwesikhashana okuphoqelelwe nokufushane komzimba, okukhumbuza kakhulu ukozela okungaphezulu.
Bhukuda uphefumule
Imvelo inciphise oshaka ngesikhumba sabo sokubhukuda (okukhona kuzo zonke izinhlanzi ezinamathambo), okunxephezela ukungahambi kahle kwabo ngamathambo e-cartilaginous, isibindi esikhulu namaphiko. Oshaka abaningi abayeki ukunyakaza, njengoba ukuma kumholela ekushoneleni ngokushesha.
Esimweni esizuzisa kakhulu kunabanye oshaka besihlabathi, abafunde ukugwinya umoya nokuwugcina ephaketheni lesisu elikhethekile. Isitho esakhiwe se-hydrostatic (swim bladder replacement) asibhekene nje kuphela nokushuba koshaka besihlabathi, kepha futhi sikwenza kube lula kakhulu impilo yaso, kufaka phakathi amakhefu amafushane okuphumula.
Phefumula ukuze uphile
Oshaka, njengazo zonke izinhlanzi, badinga umoya-mpilo, abawuthola emanzini adluliswa ngemiphunga yabo.
Izitho zokuphefumula zikashaka yizikhwama ze-gill eziphuma ekuvulekeni kwangaphakathi ku-pharynx, futhi zangaphandle zibheke ebusweni bomzimba (ezinhlangothini zekhanda). Izazi zezinto eziphilayo zibala kusuka kumabhangqa ama-5 kuye kwayi-7 ama-gill slits ezinhlotsheni ezahlukahlukene, ezibekwe phambi kwamaphiko e-pectoral. Lapho uphefumula, igazi namanzi kuhamba ngokulandelana.
Kuyathakazelisa! Ezinhlanzi ezingamathambo, amanzi ageza izifuba ngenxa yokuhamba kwezembozo zamagill, ezingekho koshaka. Ngakho-ke, izinhlanzi ezihamba ngemithambo zihambisa amanzi eceleni kwe-lateral gill slits: ingena emlonyeni futhi igeleze ngaphandle kwezingcezu.
Ukugcina ukuphefumula kungami, ushaka kufanele aqhubeke ngokuqhubekayo evule umlomo. Manje sekucacile ukuthi kungani oshaka, ababekwe echibini elincane, bashaya imilomo yabo evulekile: abanakho ukunyakaza, ngakho-ke i-oxygen.
Oshaka balala kanjani baphumule
Abanye ochwepheshe bezichthyologists banesiqiniseko sokuthi izinhlobo ezithile zoshaka ziyakwazi ukulala noma ukuphumula, kumise umsebenzi wazo wokugcina unomphela.
Kuyaziwa ukuthi bayakwazi ukulala benganyakazi phansi:
- umsele wamanzi amhlophe;
- ingwe oshaka;
- sobbegongs;
- izingelosi zasolwandle;
- mustachioed nurse shark.
Lezi zinhlobo ze-benthic zifunde ukumpompa amanzi ngemigodi besebenzisa ukuvula / ukuvala umlomo nomsebenzi wokuvumelanisa wemisipha ye-gill kanye nepharynx. Izimbobo ezingemuva kwamehlo (squirt) nazo zisiza ukujikeleza okungcono kwamanzi.
Izazi zezinto eziphilayo ziphakamisa ukuthi oshaka be-pelagic (abahlala ekujuleni okukhulu) baphoqeleka ukuthi bahambe njalo ngenxa yobuthakathaka bemisipha ye-gill, engakwazi ukubhekana nokumpompa amanzi ngemigodi.
Kuyathakazelisa! Ososayensi bacabange ukuthi oshaka be-pelagic (njengamahlengethwa) bayalala, bacishe ama-hemispheres angakwesobunxele nangakwesokudla ngokuhlukile.
Kunezinye izinhlobo ezichaza indlela yokulala koshaka. Kukholelwa ukuthi ezinye izinhlobo zibhukuda zize zifike ogwini, zilungisa umzimba phakathi kwamatshe: ngenkathi ukugeleza kwamanzi okudingekayo ekuphefumuleni kudalwa igagasi lolwandle.
Ngokusho kochthyologists, oshaka bangalala phansi uma bethola indawo ecashile enokushintshashintsha okubonakalayo endaweni yasemanzini (kusuka emisakazweni emikhulu noma emikhulu). Ngokulala ubusika obunjalo, ukusetshenziswa komoya-mpilo kuncishiswe kwaba cishe zero.
Izici zabo zokulala zatholwa nakuma-mustachioed dog shark, ezaba yizinto zokucwaninga ngoochwepheshe be-neurophysiologists. Ososayensi baphethe ngokuthi izifundo zabo zokuhlola zingalala ... ngenkathi zihamba, ngoba isikhungo sezinzwa esisungula umzimba sisezintanjeni zomgogodla. Lokhu kusho ukuthi ushaka uyakwazi ukubhukuda ephusheni, phambilini enqamule ubuchopho.
Amaholide e-Caribbean
Uchungechunge lokubukwa koshaka lwenziwa eduze neNhlonhlo Yucatan ehlukanisa iGulf of Mexico neCaribbean. Eduze nenhlonhlo, kunomhume ongaphansi kwamanzi, lapho abacwaningi bathole khona ukulala ngokushesha (uma uthi nhlá) oshaka bamakhorali. Bona, ngokungafani noshaka we-whitetip, babhekwa njengababhukudi abakhuthele, abagijimela ngokungakhathali kukholamu lamanzi.
Lapho ihlolisiswa, kwavela ukuthi inhlanzi yenze ukuphefumula okungu-20-28 ngomzuzu, isebenzisa imisipha yegill nomlomo. Ososayensi babiza le ndlela ukugeleza-noma ukungenisa umoya komoya nje: ama-gill ahlanzwa ngamanzi avela emithonjeni emisha econsa esuka ezansi.
Ichthyologists bayaqiniseka ukuthi oshaka bachitha izinsuku eziningana emihumeni ngomsinga obuthakathaka, beka phansi phansi bawele kuhlobo lwe-torpor, lapho yonke imisebenzi yomzimba yehliswa kakhulu.
Kuyathakazelisa! Baphinde bathola ukuthi emanzini omhume (sibonga iziphethu ezintsha) kwakukhona umoya-mpilo omningi nosawoti omncane. Izazi zezinto eziphilayo zaphakamisa ukuthi amanzi aguquliwe asebenza njengesidakamizwa esivimbela oshaka.
Ngokombono wososayensi, bonke abanye emhumeni bebengafani ncamashi nephupho: amehlo oshaka alandela ukunyakaza kwabatshuzi be-scuba.... Ngemuva kwesikhashana, kwaphinde kwaziwa ukuthi, ngaphezu koshaka bamadwala, ezinye izinhlobo zihlelwe ukuthi ziphumule emathafeni, kufaka phakathi i-nurse shark, i-sand shark, i-Caribbean, i-blue ne-bull shark.
