Breakthrough Could Save Northern White Rhino From Extinction

The last male northern white rhino in the world, Sudan, died earlier this year.

There are just two northern white rhinos left in the entire world, but a scientific breakthrough using a hybrid embryo could save the species from extinction.

A team of researchers have successfully created viable embryos using the sperm from two male northern white rhinos.

The last male northern white rhino, Sudan, died earlier this year.

There are now just two northern white rhinos in the world, a mother and daughter called Najin and Fatu, so the risky procedure was tested on 12 southern white rhinos, a closely related subspecies which numbers about 20,000.

If successful, researchers hope to recreate the results in Najin and Fatu to produce a northern white rhino calf within the next few years.

"Within three years we hope to have the first (northern white) rhino calf born," said co-lead researcher Thomas Hildebrandt in Reuters.

How do you impregnate a rhino?

An operator guides an instrument inside the rectum of an anaesthetised white rhinoceros. Photo: Nature Communications.

It's been more than two decades in the making. Back in 2008, Hildebrandt told reporters he realised there was "no chance" to save the white rhino with techniques available at the time, so researchers began collecting semen in the hope of saving the species.

The team of researchers, which published their research in the Nature Communications journal, adapted existing reproductive techniques used in horses.

"The amount of semen is limited, is of poor quality, and has been obtained from only three bulls," the research paper said.

"This made ICSI [Intracytoplasmic Sperm Injection], a routine procedure in horses, the only option that would lead to success."

They managed to extract eggs from 12 southern white rhinos -- a risky procedure in and of itself -- and inject them with the hybrid sperm.

"You can's reach the ovaries by hand, so we developed a special device," Hildebrandt told BBC News. "We used ultrasound to very precisely inject a needle into [the area of the ovary that releases] eggs."

Of the 13 eggs injected, four developed into blastocysts (an early embryo), all of which showed signs of healthy embryonic stem cells.

But they're still relying on a fair bit of luck. It is unclear at this stage if Najin of Fatu have viable eggs.

"Nobody has any idea about how they look inside," Hildebrandt told ABC. "The younger female is 18, the older female is 26, so we're running out of time."