未出生的幼鯊會(huì)在子宮之間游動(dòng)，吞食兄弟姐妹

未出生的幼鯊會(huì)在子宮之間游動(dòng)，吞食兄弟姐妹

As macabre as it seems, it's not exactly a secret that in some species of shark the unborn dine on their siblings while still developing in the womb.

盡管看起來(lái)令人毛骨悚然，但在某些種類的鯊魚中，未出生的幼體在子宮內(nèi)發(fā)育的同時(shí)，卻以兄弟姐妹為食，這并不是什么秘密。

But it turns out we don't know the half of it. A novel kind of ultrasound device has provided biologists with a detailed view of this common act of cannibalism, and in 2018 it revealed they don't just nibble on their neighbour. Embryos will travel between wombs to feast.

但事實(shí)證明我們只知其一不知其二。一種新型的超聲波裝置為生物學(xué)家提供了這種常見的食人行為的詳細(xì)視圖，并在2018年揭示出它們不僅僅是在蠶食它們的鄰居，胚胎還會(huì)在子宮之間游走以飽餐一頓。

No, that's not a typo. Many species of shark mature their eggs or gestate embryos in a left and a right uterus.

是的，我沒打錯(cuò)字。許多種類的鯊魚用左子宮和右子宮來(lái)孕育它們的卵或胚胎。

(Tomita etal/Ethology)

For most animals, embryonic movement is rather limited to a bit of squirming and the occasional flip. Even for young that aren't anchored to a placenta, gestation is thought to be a rather sedentary affair.

對(duì)大多數(shù)動(dòng)物來(lái)說(shuō)，胚胎期的活動(dòng)相當(dāng)有限，只有一點(diǎn)蠕動(dòng)和偶爾的翻轉(zhuǎn)。即使對(duì)于沒有固定在胎盤上的嬰兒，妊娠也被認(rèn)為是一種相對(duì)靜止的事情。

So researchers from Okinawa Churaumi Aquarium in Motobu, Japan, were surprised to find the unborn pups of captive tawny nurse sharks (Nebrius ferrugineus) not only moving around their own uterus, but moving house altogether.

因此，來(lái)自日本Motobu市沖繩縣美之海水族館的研究人員驚奇地發(fā)現(xiàn)，圈養(yǎng)的黃褐色護(hù)士鯊(Nebrius ferrugineus)未出生的幼崽不僅在自己的子宮里動(dòng)來(lái)動(dòng)去，而且還在搬家。

The discovery came courtesy of a fancy new piece of equipment that allows the kind of ultrasound device you'd use to scan a human pregnancy to be packed up and carried underwater.

這一發(fā)現(xiàn)得益于一種新穎的設(shè)備，這種設(shè)備可以將你用來(lái)掃描人類懷孕的超聲波設(shè)備打包并運(yùn)到水下。

Over several years, the researchers studied a trio of pregnant tawny nurse sharks on display in an aquarium exhibition tank, capturing more than 40 ultrasound clips.

幾年來(lái)，研究人員研究了在水族館展覽池中展出的三只懷孕的黃褐色護(hù)士鯊，捕捉了40多個(gè)超聲波片段。

The results provided a family album on a time line, where up to four pups could be seen wiggling about inside each mother.

研究結(jié)果提供了一個(gè)按時(shí)間排列的家庭相冊(cè)，在相冊(cè)中可以看到多達(dá)四只幼崽在各自母親的身體里扭動(dòng)。

In one mother, embryos swapped sides three times. In another, the movement was far more extreme – a total of 24 migrations were recorded across the duration of the pregnancy.

在一個(gè)母親身上，胚胎交換了三次。在另一個(gè)母親身上，這種移動(dòng)則更極端——在整個(gè)懷孕期間共記錄到24次遷徙。

(Tomita etal/Ethology)

One of the scans showed the actual room swap taking place, showing an embryo hurriedly pushing its way from one uterus to the other.

其中一項(xiàng)掃描展示了真實(shí)的遷徙過(guò)程，顯示了一個(gè)胚胎從一個(gè)子宮快速地移向另一個(gè)子宮。

We're not talking a leisurely stroll here either. The pup swam at a speedy eight centimetres per second.

它們可不是在閑庭散步，這個(gè)胚胎以每秒8厘米的速度游了過(guò)去。

One of the female sharks started her pregnancy with two pups in each uterus. After some back and forth, four soon became three. Just under two months later, there were two.

其中一只雌性鯊魚開始懷孕時(shí)，子宮里各有兩只幼崽。來(lái)回幾次之后，四個(gè)很快變成了三個(gè)。不到兩個(gè)月，就只有兩個(gè)了。

By the end of the gestation just a single, no doubt smugly satisfied, winner remained.

到妊娠期結(jié)束時(shí)，毫無(wú)疑問(wèn)，只有一個(gè)得意的贏家留了下來(lái)。