Pregnant rhino may help save sub­species

The Republican Herald - - SCIENCE -

SAN DIEGO — A south­ern white rhino has be­come pregnant through ar­ti­fi­cial in­sem­i­na­tion at the San Diego Zoo Safari Park — giv­ing hope for efforts to save a sub­species of one of the world’s most rec­og­niz­able an­i­mals, re­searchers an­nounced Thurs­day.

Sci­en­tists will be watch­ing closely to see if the rhino named Vic­to­ria can carry her calf to term over 16 to 18 months of ges­ta­tion.

If she does, re­searchers hope some­day she could serve as a sur­ro­gate mother and could give birth to the re­lated north­ern white rhino, whose pop­u­la­tion is down to two fe­males af­ter decades of dec­i­ma­tion by poach­ers. The mother and daugh­ter north­ern white rhi­nos live in a Kenya wildlife pre­serve but are not ca­pa­ble of bear­ing calves.

News of Vic­to­ria’s preg­nancy was con­firmed two months af­ter the death of the last north­ern white male rhino named Su­dan, who was also at the Kenya pre­serve and was eu­th­a­nized be­cause of ail­ing health in old age.

Vic­to­ria is the first of six fe­male south­ern white rhi­nos the San Diego Zoo In­sti­tute for Con­ser­va­tion Re­search is test­ing to de­ter­mine if they are fit to be sur­ro­gate moth­ers. If she and the oth­ers are deemed fit to do so, they could carry north­ern white rhino em­bryos some­time within the next decade as sci­en­tists work to re-cre­ate north­ern white rhino em­bryos.

There are no north­ern white rhino eggs so cre­at­ing an em­bryo would re­quire us­ing ge­netic tech­nol­ogy. Sci­en­tists plan to use frozen skin cells from dead north­ern white rhi­nos to trans­form them into stem cells and even­tu­ally sperm and eggs. Then the sci­en­tists would use in vitro fer­til­iza­tion to cre­ate em­bryos that would be put in the six fe­male rhi­nos.

“The con­fir­ma­tion of this preg­nancy through ar­ti­fi­cial in­sem­i­na­tion rep­re­sents an historic event for our or­ga­ni­za­tion but also a crit­i­cal step in our ef­fort to save the north­ern white rhino,” said Bar­bara Dur­rant, di­rec­tor of re­pro­duc­tive Sci­ences at the San Diego Zoo In­sti­tute for Con­ser­va­tion Re­search.

But more chal­lenges lie ahead, with ar­ti­fi­cial in­sem­i­na­tion of rhi­nos in zoos rare so far and re­sult­ing in only a few births.

Vic­to­ria is a healthy 747-pound rhino es­ti­mated to be seven years old.

She and the other five fe­male rhi­nos that range in age from four to seven years old were all born in the wild and re­lo­cated to San Diego’s Safari Park in 2015. Sci­en­tists will soon start de­vel­op­ing ar­ti­fi­cial in­sem­i­na­tion tech­niques and em­bryo trans­fer tech­niques for them. The rhi­nos also un­dergo weekly ul­tra­sounds.

“We will know that they have proven them­selves to be ca­pa­ble of car­ry­ing a fe­tus to term be­fore we would risk putting a pre­cious north­ern white rhino em­bryo into one of these south­ern white rhi­nos as a sur­ro­gate,” Dur­rant said.

While em­bryos have been cre­ated for south­ern white rhi­nos, they haven’t been for north­ern white rhi­nos.

The San Diego Zoo In­sti­tute for Con­ser­va­tion Re­search has the cell lines of 12 dif­fer­ent north­ern white rhi­nos stored in freez­ing tem­per­a­tures at its “Frozen Zoo.”

The ul­ti­mate goal is to cre­ate a herd of five to 15 north­ern white rhi­nos that would be re­turned to their nat­u­ral habi­tat in Africa.

AS­SO­CI­ATED PRESS

Vic­to­ria, a pregnant south­ern white rhino, roams its en­clo­sure Thurs­day at San Diego Zoo Safari Park in Es­con­dido, Calif. Its preg­nancy through ar­ti­fi­cial in­sem­i­na­tion is giv­ing hope for efforts to save a sub­species.

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