[(Title)] There are only two northern white rhinos left. Scientists hope hybrid embryos will save the species.

Scientists say they're several steps closer to perfecting a method that could prevent the extinction of northern white rhinos, of which only two animals are known still to be alive.

科学家表示，他们距离完善一种可以防止北方白犀牛灭绝的方法还有几步之遥，目前只有两只白犀牛仍然活着。

According to a paper published Wednesday in the journal Nature Communications, researchers have succeeded in creating embryos using frozen northern white rhino sperm and eggs from a southern white rhino, a closely related sub-species.

根据周三出版的《自然交流》杂志上的一篇文章，研究人员利用与密切相关的副物种——南部的白犀牛精子和卵子成功创造了胚胎。

It's the first time such hybrid embryos have been created and the scientists from Germany, Italy and the Czech Republic say it could provide a pathway to saving the critically endangered northern white rhino after the last male, called Sudan, died in March.

这是第一次创造这样的杂交胚胎，来自德国，意大利和捷克共和国的科学家表示，它可以提供一条途径来拯救极度濒危的北方白犀牛，因为最后一只名叫苏丹的雄性在3月份死亡。

They plan to harvest the egg cells of the two surviving female rhinos soon and use preserved sperm to produce "pure" northern white rhino embryos.

他们计划很快收获两个幸存的雌犀牛的卵细胞，并使用保存过的精子生产出“纯”的北部白犀胚胎。

Since the females, a mother and daughter called Najin and Fatu, are unable to bear offspring themselves, the embryos would be implanted in a southern white rhino surrogate.

由于雌性，一个名为Najin和Fatu的母亲和女儿无法自己生育后代，所以胚胎将被植入南部的白犀牛替代品中。

In order to increase the supply of eggs and preserve the northern white rhino's genetic diversity, scientists are also working on a second method that would coax frozen skin cells from deceased animals into becoming egg cells, a procedure that has already succeeded in mice.

为了增加卵子的供应并保护北方白犀牛的遗传多样性，科学家们还在研究第二种方法，即将已死亡动物的冷冻皮肤细胞诱导成卵细胞，这种方法已成功应用于老鼠体内。

Thomas Hildebrandt, of the Leibniz Institute for Zoo and Wildlife Research in Berlin, said researchers hope the first northern white rhino calf will be born in about three years.

位于柏林的雷布尼茨动物园和野生动物研究所的托马斯·希尔德邦特表示，研究人员希望北方第一只白犀牛将在大约三年内出生。

"We are quite confident with the technology we have developed," he said during a telephone conference with reporters detailing the research.

“我们对自己开发的技术相当有信心，”他在电话会议上与记者们详细介绍研究情况时说。

Saving the northern white rhino has become an international effort, with cooperation but also some rivalry among scientists and institutions around the world, including zoos in San Diego and Cincinnati.

拯救北部的白犀已经成为一项国际努力，全世界科学家和机构，包括圣地亚哥和辛辛那提动物园之间的合作和竞争也成为一项国际努力。

Some experts have criticized the effort however, saying it comes too late.

然而，一些专家批评了这项努力，因为它来的台湾。

"I have no doubt that its purely scientific merit is laudable and it might have some application to endangered species conservation in the future," said Richard Kock, a conservationist at Britain's Royal Veterinary College who has worked extensively in Africa. 

“我毫不怀疑它纯粹的科学价值是值得称赞的，未来可能会对濒危物种的保护有所应用，”英国皇家兽医学院的环保学家理查德科克说。他曾在非洲广泛工作过。 

Kock and fellow conservationists warned against focusing only on the northern white rhino sub-species, noting that its southern cousin has come back from the brink of extinction and now numbers some 21,000 individuals.

科克和同样的自然资源保护主义者警告说，不要只关注北部的白犀牛亚物种，它南部的表弟已经从灭绝的边缘回来，现在约有21,000只。

Instead, they suggested, work should focus on saving other endangered rhino species that can still be found in the wild.

相反，他们建议，应将工作重点放在拯救仍能在野外发现的其他濒临灭绝的犀牛物种上。

"Assisted reproductive technologies are very expensive and their success is far from guaranteed.

"辅助生殖技术非常昂贵，而且其成功远远不能得到保证。

Meanwhile, we don't have enough funding to conserve the other four rhino species, all of which are more threatened with extinction than the white rhino," said Bob Smith, director of the Durrell Institute of Conservation and Ecology at the University of Kent, England.

英国肯特大学保护生态研究所所长鲍勃·史密斯说，同时，我们没有足够的资金保护其他四种犀牛，因为与白犀牛相比，这些犀牛灭绝的危险更大。

Hildebrandt insisted the effort is worthwhile. "The northern white rhino didn't fail in evolution," he said. "It failed because it's not bulletproof. It was slaughtered by criminals which went for the horn because the horn costs more than gold."

希尔德布兰特坚持认为这种努力是值得的。 “北方的白犀牛并没有在进化中失败，”他说。 “它失败了，因为它不是防弹的。它被歹徒屠杀了，因为犀牛角比黄金更昂贵。”

Northern white rhinos were once abundant across Central and East Africa, but conflicts and poaching wiped them from their natural habitat.

北白犀牛曾经遍布中部和东部非洲，但冲突和偷猎把它们从自然栖息地抹去。

The rhino's disappearance has left a void in the region's ecosystem that could have significant impacts in the future, Hildebrandt said. "We have the tools in our hands to correct that."

希尔德邦特说，犀牛的消失给该地区的生态系统留下了一个空洞，这在将来可能会产生重大影响。

Cesare Galli, whose Italy-based company Avantea has lengthy experience with the artificial reproduction of horses, said recent advances in stem cell technology could help the rhino preservation effort.

Cesare Galli，其意大利公司Avantea在人工繁殖马方面拥有丰富的经验，他说干细胞技术的最新进展可以帮助犀牛保护工作。

The team is hoping that within a decade, scientists will be able to produce new rhino eggs from frozen skin cells

研究小组希望科学家们能在十年内从冷冻的皮肤细胞中产生新的犀牛卵。

Jan Stejskal, a spokesman for Dvur Kralove Zoo in the Czech Republic, which has a long history of rhino conservation, said scientists hope to travel to Kenya before the end of the year.

捷克共和国Dvur Kralow动物园发言人Jan Stejskal说，科学家希望在年底前前往肯尼亚，因为该动物园在犀牛保护方面历史悠久。

They are still waiting for permission from Kenyan authorities to perform the delicate procedure of removing egg cells from Najin and Fatu.

他们仍在等待肯尼亚当局的许可，以完成从纳津和巴图清除卵细胞的微妙程序。

While the scientists are confident about being able to harvest eggs from the two females, questions remain over the risk to the rare animals' health.

尽管科学家确信能够从两个雌性体内摘取卵子，但人们仍然存在着对稀有动物健康的风险问题。

"We as scientists are highly afraid that something unexpected happens during that procedure," said Hildebrandt. "That would be a nightmare."

“我们科学家非常担心这一过程会发生一些意外，”希尔德邦特说，“这将是一场噩梦。”