How Northern White Rhino Egg Extraction May Save the Species

Analysis by Dr. Karen Shaw Becker

northern white rhino

Story at-a-glance -

  • In an effort to preserve the northern white rhino species, perilously close to extinction, teams of scientists worked together to extract and transfer eggs from the remaining two females, Najin and Fatu
  • Scientists hoped to get at least a few mature eggs that could be artificially inseminated with frozen sperm from two northern white rhino bulls, named Suni and Saut
  • Ten eggs were harvested and seven were artificially inseminated with frozen sperm from two northern white rhino bulls, Suni and Saut, using Intra Cytoplasm Sperm Injection, or ICSI
  • Najin’s father, Sudan, was a northern white rhino with the distinction of being the last male of his species, as well as the focus of a fundraising effort for the Assisted Reproductive Techniques (ART) program
  • Although it’s been illegal to trade rhino horn in China since 1993, the poaching of northern white rhino, as well as other species, is the main reason why the animal is down to just two females on the planet

Najin and Fatu are the only two females remaining of the northern white rhino species, but sadly, neither has been able to maintain a pregnancy resulting in a live birth. As a result, both rhinos underwent egg extraction procedures recently in hopes that the prehistoric-looking animals would be able to reproduce through the use of a surrogate from a close female relative — most likely a southern white rhino.

The procedure was made possible through the collaborative efforts of wildlife personnel from the Leibniz Institute for Zoo and Wildlife Research in Berlin,1 biotechnology research lab Avantea in Cremona, Italy,2 Dvur Králové Zoo in the Czech Republic,3 Ol Pejeta Conservancy,4 the home of Najin and Fatu and the largest black rhino sanctuary in east Africa, and the Kenya Wildlife Service.5

According to researchers at Avantea, 10 eggs were harvested from Najin and Fatu; seven were "successfully matured and artificially inseminated" with frozen sperm from two northern white rhino bulls, Suni and Saut, using Intra Cytoplasm Sperm Injection or ICSI. Cesare Galli, who led the procedure, explained:

"We were surprised by the high rate of maturation achieved as we do not get such high rates (comparable to what we get with horse oocytes) with southern white rhino females in European zoos.

The semen of Saut was very difficult to work with and to find three live sperms needed for the eggs of Najin we had to thaw two batches of semen. Now the injected oocytes are incubated and we need to wait to see if any viable embryo develop to the stage where it can be cryopreserved for later transfer."6

Robert Hermes, a veterinarian researcher at the Leibniz Institute, noted the elation expressed by everyone involved following the first portion of the procedure on 28-year-old Najin and her 18-year-old daughter, Fatu, both said to be recovering well. Hermes noted, "We were hoping to get a few eggs from them and our expectations have been exceeded by getting five ... from each."7

Last of the Northern White Rhinos — Hope for the Species

Najin and Fatu, the mother and daughter rhinos that underwent the egg extraction procedure, came from hardy stock. Najin's father, Sudan, was a northern white rhino with the distinction of being the last male of his species. Around 20,000 southern white rhinos remain in Africa, according to AP News, which notes:

"Sudan was the last of his kind to be born in the wild, in the country that is his namesake. He was taken to the Czech zoo and then transferred to Kenya in 2009, along with the only other remaining northern white rhinos, the two females and a male who died in 2014."8

Ol Pejeta Conservancy, in partnership with the dating app, Tinder, sought to raise $9 million for the Assisted Reproductive Techniques (ART) program. As such, Sudan was declared the "Most Eligible Bachelor in the World" and became the center of an ambitious effort to save the subspecies from extinction, especially since poaching diminished their numbers over several decades.

For that fact alone, Sudan and the two surviving rhinos were placed under armed guard around the clock, and fed a special diet. The goal of all the different agencies, from biotechnology research teams to veterinarians to wildlife conservationists, was to create a herd of at least five to as many as 15 northern white rhinos. The rest of the plan was to return the animals to a natural habitat in Africa that would allow them to thrive, even though the scientists knew it could take decades to complete such a mission.

However, while the rhinos were observed mating, no offspring was forthcoming. Sadly, Sudan, described as "gentle" by the rangers caring for him, was euthanized in March of 2018 due to age-related health issues.

The Potential Extinction of Northern White Rhinos

The southern white rhino as well as the black rhino are still under constant threat of extinction due to relentless poaching, primarily for their horns, which are sold on the black market, principally in China, where it's been illegal to trade rhino horn since 1993. Unfortunately, the market continues to thrive, according to National Geographic, which adds:

"Rhinos are being decimated by poaching. In South Africa, home to almost 80 percent of the world's rhinos, more than a thousand have been slaughtered annually during the past four years. That's 8,000 percent more than were killed a decade ago, in 2007. Last year rangers in Kruger National Park were called out to stop more than 2,800 incursions by poachers — roughly eight every day."9

How to Propagate a Dying Rhino Species

Although Sudan's death was noted by the world as a sad day, it didn't end the efforts of conservationists to save a subspecies of the magnificent and beloved rhino species. Their energies for their propagation were then pinned on Sudan's stored semen, as well as that of four other rhinos that had also died.

Perfecting the in vitro fertilization techniques to use on the rhinos became another crucial focus, as well as keeping Najin and Fatu alive and well, at least until their eggs could be harvested, since the future of the species may be dependent on their survival.

So for now, the world waits to see if embryos develop after all scientists have done to help preserve the species from extinction. According to Smithsonian Magazine, "If they succeed, it will be the first time a virtually extinct mammal with no living males has been brought back from the brink."10

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