For hu­mans, the city proves prob­lem­atic

A fran­tic quest to save the north­ern white rhino from ex­tinc­tion

Popular Science - - CONTENTS -

THOMAS HILDEBRANDT FIRST SAW THE IN­SIDE of an ele­phant in 1990. With the mam­moth car­cass laid across his lab bench at the Leib­niz In­sti­tute in Ber­lin, where the Ger­man ve­teri­nary stu­dent was work­ing that sum­mer, he pon­dered his the­sis on us­ing hu­man-fer­til­ity tech­niques to save en­dan­gered wildlife. Hildebrandt, then 27, was taken aback by the mam­mal’s bizarre re­pro­duc­tive tract. The pas­sage was 10 feet long and con­cealed by a folded vagi­nal open­ing as nar­row as a sun­flower seed. The task of ar­ti­fi­cially in­sem­i­nat­ing an ele­phant, he learned in that mo­ment, would mean get­ting shoul­der-deep in many a cav­ernous nether re­gion.

“I’ve al­ways loved to solve prob­lems other peo­ple can­not,” re­calls Hildebrandt, now 54, of his 26-year ca­reer as an an­i­mal-fer­til­ity ex­pert and pi­o­neer of en­dan­gered-species in­sem­i­na­tion. The pro­ce­dures he’s de­vel­oped take hours and de­mand a steady hand. Today, as the lead re­pro­duc­tion spe­cial­ist at the Leib­niz In­sti­tute for Zoo and Wildlife Re­search, he has more prac­tice than any­one. He’s helped con­ceive more than 50 ele­phant calves, per­formed CPR on rhi­nos se­dated for surgery by jump­ing on rib cages, and patented a slew of tech­niques and de­vices for mak­ing ba­bies in these be­he­moths.

This year, he’ll at­tempt his great­est feat yet: the first ever suc­cess­ful in vitro fer­til­iza­tion (IVF) of a rhino. De­spite su­per­fi­cial sim­i­lar­i­ties to its trunked cousins, the beast’s anatomy poses a new, high-stakes bi­o­log­i­cal puz­zle. If he can crack it, how­ever, Hildebrandt could pull the north­ern white back from the brink.

Colo­nial-era hunt­ing, poach­ing, and habi­tat loss have put all rhino species at risk. Though peo­ple have used the crea­ture’s horn


in tra­di­tional medicine for thou­sands of years, a re­cent surge in de­mand in Asia sent pop­u­la­tions crash­ing. South Africa lost 13 in­di­vid­u­als out of some 15,000 to poach­ing in 2007; in 2014, the num­ber hit 1,215. Three of the world’s five rhino species are now crit­i­cally en­dan­gered, a des­ig­na­tion mark­ing them as at an ex­tremely high risk of ex­tinc­tion. But the north­ern white rhino oc­cu­pies a uniquely pre­car­i­ous po­si­tion.

Only two—both fe­males in­ca­pable of car­ry­ing calves— re­main at the Ol Pe­jeta Con­ser­vancy in Laikipia, Kenya. Na­jin, age 28, has Achilles ten­dons that could rup­ture un­der the weight of a preg­nancy. Fatu is younger but bar­ren, thanks to a uter­ine in­fec­tion. The world’s last male, Su­dan, died in March at the age of 45.

But the beloved bull could still sire a calf. Sperm from Su­dan (and four other males) is on ice, and Hildebrandt hopes to har­vest Fatu and Na­jin’s eggs. The vet and his in­ter­na­tional part­ners will fer­til­ize the ova in an Ital­ian lab, and re­turn the em­bryo to Ol Pe­jeta, where the kid-car­ry­ing will fall to a fam­ily friend.

With their ro­bust pop­u­la­tion of 20,000 liv­ing in­di­vid­u­als, Hildebrandt be­lieves that the south­ern white rhino—tech­ni­cally the same species as its en­dan­gered north­ern cousin but so dis­tinct from years of sep­a­ra­tion that many ex­perts ar­gue oth­er­wise— can stand to spare a few fe­males to serve as sur­ro­gates.

THE NO­TION TO MAKE TEST-TUBE off­spring of at-risk wildlife came to Hildebrandt through serendip­ity. While study­ing to be­come a live­stock vet in the late ’80s, he vis­ited his fu­ture wife. She was work­ing as a birthing as­sis­tant at Char­ité Hospi­tal in East Ber­lin, which just so hap­pened to pro­duce the

first hu­man IVF birth in the re­gion. The fa­cil­ity in­spired him to re­di­rect his fo­cus and tackle a the­sis on us­ing the tech­nique to re­vive en­dan­gered species. “At the time, no one—not even the so-called ele­phant ex­perts—knew how to use ar­ti­fi­cial in­sem­i­na­tion to help these an­i­mals re­pro­duce,” Hildebrandt re­calls.

That’s be­cause decades of suc­cesses in hu­man IVF—seed­ing an egg in a lab­o­ra­tory be­fore im­plant­ing it in a mother or sur­ro­gate— don’t di­rectly ap­ply to other an­i­mals. Since its in­tro­duc­tion in 1978, the U.S. alone has seen some 1 mil­lion ba­bies born with the help of the method. But, some­what un­sur­pris­ingly, there are nearly as many vari­a­tions on the me­chan­ics of re­pro­duc­tion as there are species. Pan­das, for in­stance, can con­ceive only a few days out of each year. Whip­tail lizards make em­bryos without male in­ter­ven­tion. Fruit flies have enor­mous sperm (the in­sect is about ⅛ inch; its swim­mers, more than 2 inches).

There are even dis­par­i­ties among close rel­a­tives, like species of rhino, so Hildebrandt must de­velop or re­fine unique tools and pro­ce­dures for each new mam­malian pa­tient. Ex­tract­ing eggs is the most del­i­cate part of the en­deavor. Though he’s al­ready patented a hand­held nee­dle ca­pa­ble of reach­ing the ovaries through the rec­tum of the black rhino, col­lect­ing whites’ eggs de­mands a new twist on the tool. The cus­tom probe still slips through the rec­tum but must span 6 feet long to al­low the vet to snake it just past a ma­jor blood ves­sel that, if punc­tured, would cause the fe­male to bleed out. Such risk de­mands ex­treme cau­tion from the team; after all, there are only two north­ern white rhi­nos re­main­ing.

“When it comes to us­ing new tech­niques on en­dan­gered species, we don’t have the lux­ury of trial and er­ror,” Hildebrandt says. “Pre­ci­sion is es­sen­tial.” That’s why he has been us­ing south­ern whites as guinea pigs for the har­vest­ing pro­ce­dure. He and his team of nine have spent two years re­fin­ing the op­er­a­tion. They’ve suc­cess­fully har­vested eggs from 14 south­ern white fe­males in Euro­pean zoos, and none has ex­pe­ri­enced health is­sues as a re­sult.

Hildebrandt says he might move on to mak­ing a north­ern white em­bryo by the end of the year. Then, 16 to 18 months later, the world’s first test-tube rhino calf could ar­rive.

EVEN IF HILDEBRANDT SUC­CEEDS IN CRE­AT­ING mul­ti­ple calves, they could fail to propagate into a vi­able pop­u­la­tion. Two liv­ing rhi­nos and five de­ceased sperm donors don’t pro­vide the gene pool with a lot of di­ver­sity (es­pe­cially since Na­jin is Su­dan’s daugh­ter, and Fatu his grand­daugh­ter). Var­ied genes keep un­for­tu­nate mu­ta­tions from quickly spread­ing and weak­en­ing the pop­u­la­tion. Their best hope comes from po­ten­tial col­lab­o­ra­tors at the San Diego Zoo. The fa­cil­ity holds frozen adult cells from 12 north­ern whites. Jeanne Lor­ing, a stem-cell bi­ol­o­gist at the Scripps Re­search In­sti­tute in Cal­i­for­nia, is work­ing to re­pro­gram them into sperm and eggs but has yet to do so.

All these fac­tors and more make sav­ing the species “ten­u­ous,” con­cedes Ol Pe­jeta CEO Richard Vigne. And whether fu­ture gen­er­a­tions could safely re­turn to their na­tive Cen­tral African habi­tat is not his im­me­di­ate pri­or­ity. “We’re fo­cused on get­ting more north­ern whites on the ground,” he says. He be­lieves the team’s ef­forts sup­port all species of rhino by show­ing their plight to the world, and could even spark sim­i­lar ef­forts for other im­per­iled an­i­mals.

Hildebrandt him­self is con­fi­dent that a baby rhino will soon be stum­bling around Ol Pe­jeta, and has no qualms about how much sci­en­tists must med­dle to make it hap­pen. “We must save this mag­nif­i­cent crea­ture, since bar­baric hu­man ac­tions caused its ex­tinc­tion,” he says. But he warns that ef­forts will col­lapse without fund­ing. For now, the var­i­ous en­ti­ties work­ing to save the sub­species are fi­nanc­ing their own pieces of the puz­zle, and costs are con­sid­er­able. Es­tab­lish­ing a wild pop­u­la­tion of north­ern whites could take more than $6 mil­lion, and Hildebrandt’s depart­ment has less than $25,000 per year al­lo­cated to the project.

But Hildebrandt fiercely de­fends the po­ten­tial ex­pense. “I think about what peo­ple spend on cul­tural trea­sures— say, ada Vinci paint­ing—and how many species that money could save,” he says. “Los­ing species means los­ing the books of evo­lu­tion be­fore we have the chance to read them.”


Steady Hands Hildebrandt (cen­ter) would be the first to har­vest eggs from a north­ern white rhino, a po­ten­tially fa­tal pro­ce­dure.

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