WEBVTT 00:00:06.855 --> 00:00:12.955 In the savannahs of Kenya, two female northern white rhinos, Nájin and Fatu, 00:00:12.955 --> 00:00:15.565 munch contentedly on the grass. 00:00:15.565 --> 00:00:18.040 At the time of this video’s publication, 00:00:18.040 --> 00:00:23.390 these are the last two known northern white rhinos left on Earth. 00:00:23.390 --> 00:00:26.030 Their species is functionally extinct— 00:00:26.030 --> 00:00:29.990 without a male, Nájin and Fatu can’t reproduce. NOTE Paragraph 00:00:29.990 --> 00:00:34.410 And yet, there’s still hope to revive the northern white rhino. 00:00:34.410 --> 00:00:36.269 How can that be? NOTE Paragraph 00:00:36.269 --> 00:00:38.700 The story starts about 50 years ago, 00:00:38.700 --> 00:00:42.330 when poachers began illegally hunting thousands of rhinos 00:00:42.330 --> 00:00:45.340 across Africa for their horns. 00:00:45.340 --> 00:00:48.440 This, combined with civil wars in their territory, 00:00:48.440 --> 00:00:51.640 decimated northern white rhino populations. 00:00:51.640 --> 00:00:57.427 Concerned conservationists began trying to breed them in captivity in the 1970s, 00:00:57.427 --> 00:01:00.707 collecting and storing semen from males. 00:01:00.707 --> 00:01:05.474 Only four rhinos were ultimately born through the ambitious breeding program. 00:01:05.474 --> 00:01:09.824 Nájin, and her daughter Fatu were the last two. NOTE Paragraph 00:01:09.824 --> 00:01:15.440 In 2014, conservationists discovered that neither can have a calf. 00:01:15.440 --> 00:01:19.530 Though Nájin gave birth to Fatu, she now has weak hindlegs, 00:01:19.530 --> 00:01:23.437 which could harm her health if she became pregnant again. 00:01:23.437 --> 00:01:27.128 Fatu, meanwhile, has a degenerated uterine lining. 00:01:27.128 --> 00:01:34.112 Then, the last northern white rhino male of the species, Sudan, died in 2018. 00:01:34.112 --> 00:01:38.062 But there was one glimmer of hope: artificial reproduction. 00:01:38.062 --> 00:01:42.539 With no living males and no females able to carry a pregnancy, 00:01:42.539 --> 00:01:46.531 this is a complicated and risky process to say the least. 00:01:46.531 --> 00:01:51.125 Though scientists had stored semen, they would have to collect the eggs— 00:01:51.125 --> 00:01:56.759 a complex procedure that requires a female to be sedated for up to two hours. 00:01:56.759 --> 00:02:00.419 Then, they’d create a viable embryo in the lab— 00:02:00.419 --> 00:02:05.150 something that had never been done before, and no one knew how to do. 00:02:05.150 --> 00:02:06.980 Even that was just the beginning— 00:02:06.980 --> 00:02:10.341 a surrogate mother of another rhino species 00:02:10.341 --> 00:02:13.272 would have to carry the embryo to term. NOTE Paragraph 00:02:13.272 --> 00:02:17.422 Females of a closely related species, the southern white rhino, 00:02:17.422 --> 00:02:21.092 became both the key to developing a rhino embryo in a lab 00:02:21.092 --> 00:02:25.062 and the leading candidates for surrogate mothers. 00:02:25.062 --> 00:02:29.552 Northern and southern white rhinos diverged about a million of years ago 00:02:29.552 --> 00:02:33.542 into separate— though still closely-related— species. 00:02:33.542 --> 00:02:38.038 They inhabit different regions, and have slightly different physical traits. NOTE Paragraph 00:02:38.038 --> 00:02:42.108 In a fortunate coincidence, several female southern white rhinos 00:02:42.108 --> 00:02:45.042 needed treatment for their own reproductive problems, 00:02:45.042 --> 00:02:49.412 and researchers could collect eggs as part of that treatment. 00:02:49.412 --> 00:02:53.427 In Dvůr Králové Zoo in October 2015, 00:02:53.427 --> 00:02:59.111 experts of IZW Berlin began collecting eggs from southern white rhinos 00:02:59.111 --> 00:03:04.895 and sending them to Avantea, an animal reproduction laboratory in Italy. 00:03:04.895 --> 00:03:11.921 There, scientists developed and perfected a technique to create a viable embryo. NOTE Paragraph 00:03:11.921 --> 00:03:13.651 Once they mastered the technique, 00:03:13.651 --> 00:03:19.709 researchers extracted Nájin and Fatu’s eggs on August 22, 2019 00:03:19.709 --> 00:03:21.769 and flew them to Italy. 00:03:21.769 --> 00:03:25.187 Three days later, they fertilized the eggs with sperm 00:03:25.187 --> 00:03:27.737 from a northern white rhino male. 00:03:27.737 --> 00:03:32.029 After another week, two of the eggs made it to the stage of development 00:03:32.029 --> 00:03:36.111 when the embryo can be frozen and preserved for future. 00:03:36.111 --> 00:03:41.049 Another collection in December 2019 produced one more embryo. 00:03:41.049 --> 00:03:47.919 As of early 2020, the plan is to collect Nájin and Fatu’s eggs three times a year 00:03:47.919 --> 00:03:49.809 if they’re healthy enough. NOTE Paragraph 00:03:49.809 --> 00:03:51.999 In the meantime, researchers are looking for 00:03:51.999 --> 00:03:55.179 promising southern white rhino surrogate mothers— 00:03:55.179 --> 00:03:58.979 ideally who’ve carried a pregnancy to term before. 00:03:58.979 --> 00:04:02.289 The surrogacy plan is somewhat of a leap of faith— 00:04:02.289 --> 00:04:05.209 southern and northern white rhinos have interbred 00:04:05.209 --> 00:04:10.149 both during the last glacial period and more recently in 1977, 00:04:10.149 --> 00:04:13.859 so researchers are optimistic a southern white rhino 00:04:13.859 --> 00:04:17.109 would be able to carry a northern white rhino to term. 00:04:17.109 --> 00:04:20.909 Also, the two species’ pregnancies are the same length. 00:04:20.909 --> 00:04:24.879 Still, transferring an embryo to a rhino is tricky 00:04:24.879 --> 00:04:27.179 because of the shape of the cervix. NOTE Paragraph 00:04:27.179 --> 00:04:29.809 The ultimate goal, which will take decades, 00:04:29.809 --> 00:04:34.249 is to establish a breeding population of northern white rhinos 00:04:34.249 --> 00:04:36.577 in their original range. 00:04:36.577 --> 00:04:39.769 Studies suggest that we have samples from enough individuals 00:04:39.769 --> 00:04:45.420 to recreate a population with the genetic diversity the species had a century ago. NOTE Paragraph 00:04:45.420 --> 00:04:47.890 Though the specifics of this effort are unique, 00:04:47.890 --> 00:04:52.146 as more species face critical endangerment or functional extinction, 00:04:52.146 --> 00:04:55.529 it’s also an arena for big questions: 00:04:55.529 --> 00:04:59.846 do we have a responsibility to try to bring species back from the brink, 00:04:59.846 --> 00:05:03.928 especially when human actions brought them there in the first place? 00:05:03.928 --> 00:05:06.724 Are there limits to the effort we should expend 00:05:06.724 --> 00:05:10.196 on saving animals threatened with extinction?