At the time of this video's publication, these are the last two known northern white rhinos left on Earth.

在這支影片發表的同時，牠們是我們所知世界上 最後兩隻北白犀。

Their species is functionally extinct — without a male, Nájin and Fatu can't reproduce.

牠們所屬的物種正面臨功能性滅絕，沒有公犀牛， 納金和法圖無法繁殖。

And yet, there's still hope to revive the northern white rhino.

但還是有希望可以拯救北白犀。

How can that be?

怎麼可能？

The story starts about 50 years ago, when poachers began illegally hunting thousands of rhinos across Africa for their horns.

故事開始於約五十年前，當時偷獵者開始在非洲各地 非法獵捕數千隻犀牛，以取得牠們的角。

This, combined with civil wars in their territory, decimated northern white rhino populations.

這件事，再加上發生在 牠們領土上的內戰，讓北白犀的數量大減。

Concerned conservationists began trying to breed them in captivity in the 1970s, collecting and storing semen from males.

關心此事的保育人士在 1970 年代開始試圖在籠裡飼養進行育種，收集公犀牛的精液並儲存起來。

Only four rhinos were ultimately born through the ambitious breeding program.

這個野心勃勃的繁殖計畫最終只產出了四隻犀牛。

Nájin, and her daughter Fatu were the last two.

納金和牠的女兒法圖是最後兩隻。

In 2014, conservationists discovered that neither can have a calf.

在 2014 年時，保育人士發現牠們都無法懷小犀牛。

Though Nájin gave birth to Fatu, she now has weak hind legs, which could harm her health if she became pregnant again.

雖然納金生出了法圖， 但牠現在的後腿太弱，如果牠再懷孕，會對牠的健康有害。

Fatu, meanwhile, has a degenerated uterine lining.

至於法圖，牠的子宮內膜退化。

Then, the last northern white rhino male of the species, Sudan, died in 2018.

接著，最後一隻公的北白犀，名叫蘇丹，在 2018 年死亡。

But there was one glimmer of hope: artificial reproduction.

但還有一線希望：人工繁殖。

With no living males and no females able to carry a pregnancy, this is a complicated and risky process to say the least.

沒有還活著的公犀牛， 也沒有能懷孕的母犀牛，再怎麼說這都是個複雜又冒險的過程。

Though scientists had stored semen, they would have to collect the eggs — a complex procedure that requires a female to be sedated for up to two hours.

雖然科學家已儲存精液， 他們還得收集卵子 — 這個程序很複雜，要用鎮靜劑讓母犀牛安靜兩小時。

Then, they'd create a viable embryo in the lab — something that had never been done before, and no one knew how to do.

接著，他們要在實驗室中創造 一個能活下來的胚胎 — 以前沒有人做過， 也沒有人知道要怎麼做。

Even that was just the beginning — a surrogate mother of another rhino species would have to carry the embryo to term.

那都還只是開端 — 還需要由另一種犀牛的代理孕母帶著這個胚胎一直到足月。

Females of a closely related species, the southern white rhino, became both the key to developing a rhino embryo in a lab and the leading candidates for surrogate mothers.

有一種很接近的物種是南白犀，這些母犀牛成為實驗室中發展犀牛胚胎的關鍵，以及代理孕母的主要候選者。

Northern and southern white rhinos diverged about a million of years ago into separate — though still closely-related — species.

北白犀和南白犀在大約一百萬年前分開，成為不同的 —— 但仍然很接近的 ——物種。

They inhabit different regions, and have slightly different physical traits.

牠們居住在不同的地區， 身體特徵有些微的不同。

In a fortunate coincidence, several female southern white rhinos needed treatment for their own reproductive problems, and researchers could collect eggs as part of that treatment.

在一次幸運的巧合中， 有數隻母的南白犀因為自己的生殖問題而需要治療，在治療時，研究者可以順便收集卵子。

In Dvůr Králové Zoo in October 2015, experts of IZW Berlin began collecting eggs from southern white rhinos and sending them to Avantea, an animal reproduction laboratory in Italy.

2015 年 10 月，在杜武洛夫動物園，柏林 IZW 的專家開始收集母的南白犀的卵子，再將卵子送到義大利的 Avantea 動物繁殖實驗室。

There, scientists developed and perfected a technique to create a viable embryo.

在那裡，科學家開發出很完美的技術可以創造出能活下來的胚胎。

Once they mastered the technique, researchers extracted Nájin and Fatu's eggs on August 22, 2019 and flew them to Italy.

等研究者精通該技術時，便在 2019 年八月二十二日從納金和法圖身上取得卵子，用飛機送往義大利。

Three days later, they fertilized the eggs with sperm from a northern white rhino male.

三天後，他們用公的北白犀的精子讓那些卵子受精。

After another week, two of the eggs made it to the stage of development when the embryo can be frozen and preserved for the future.

再過了一週，兩個卵子成功進入到發展階段，在此階段，可以將胚胎冰凍起來保存到未來。

Another collection in December 2019 produced one more embryo.

2019 年 12 月又做了一次採集，再產生出一個胚胎。

As of early 2020, the plan is to collect Nájin and Fatu's eggs three times a year if they're healthy enough.

2020 年初的計畫是，如果納金和法圖的健康狀況允許，一年要收集牠們的卵子三次。

In the meantime, researchers are looking for promising southern white rhino surrogate mothers — ideally who've carried a pregnancy to term before.

同時，研究者也在尋找理想的南白犀代理孕母 —— 最適合的是曾經懷孕到足月生產的犀牛。

The surrogacy plan is somewhat of a leap of faith — southern and northern white rhinos have interbred both during the last glacial period and more recently in 1977, so researchers are optimistic a southern white rhino would be able to carry a northern white rhino to term.

某種程度上，只能帶著最大的信心去進行這個代理計畫 —— 北白犀和南白犀曾經雜交過，包括在末次冰盛期以及最近一次是 1977 年，所以研究者樂觀認為南白犀能夠懷著北白犀到足月生產。

Also, the two species' pregnancies are the same length.

此外，這兩種物種的懷孕期一樣長。

Still, transferring an embryo to a rhino is tricky because of the shape of the cervix.

不過，因為子宮頸的形狀，將胚胎轉到犀牛身上是很棘手的。

The ultimate goal, which will take decades, is to establish a breeding population of northern white rhinos in their original range.

最終的目標是在數十年後，建立起一個能夠自行繁衍的北白犀族群，在原本的家園生活。

Studies suggest that we have samples from enough individuals to recreate a population with the genetic diversity the species had a century ago.

研究指出，我們有足夠的樣本來源，重新創造出的族群能夠具有牠們在一世紀前所具有的基因多樣性。

Though the specifics of this effort are unique, as more species face critical endangerment or functional extinction, it's also an arena for big questions.

雖然這項工作的細節獨特，但隨著更多物種面臨到關鍵的絕種危機或功能性滅絕，讓這項工作也成為重大問題的競技場。

Do we have a responsibility to try to bring species back from the brink, especially when human actions brought them there in the first place?

我們是否有責任要試圖把其他物種從絕種邊緣救回來？尤其是人類正是造成牠們面臨絕種的元兇？

Are there limits to the effort we should expend on saving animals threatened with extinction?

當我們把這項做法用來拯救其他受到絕種威脅的動物時，有沒有什麼限制？

How are conservationists and communities helping endangered species recover?

生態保育者和保育團體如何幫助瀕危物種生存？

See how some regions are working to repopulate vulture communities by opening vulture restaurants with this video, or explore how we can sustainably farm the ocean to prevent overfishing with this video.

觀看左方的影片，了解一些地區如何透過開設禿鷹餐館來增加禿鷹的數量，或者觀看右方的影片，探索如何持續養殖海洋以防止過度捕撈。