Scientists try to create first rhino test tube baby to save near-extinct species

The long days of summer offer little escape for the scientists of Berlin's Leibniz Institute for Zoo and Wildlife Research.

Together with an international team of reproductive and veterinary experts, they are trying to solve one of the most pressing problems in worldwide conservation today; they want to save a magnificent yet thoroughly beleaguered African mammal from extinction.

It is this troublesome issue that brought Sky News to a research building at the Schwerin Zoo in northern Germany.

Inside a concrete-reinforced pen paced a southern white rhino called Karen.

The 17-year old female had been selected for a critically important experiment.

The scientists were going to try and turn her into a mother with fertilised eggs - or embryos - created in the lab.

Theoretically at least, in vitro fertilisation - or this '"rhino IVF" - has the potential to save the northern white rhino, a once-numerous grazer which ranged over large parts of central and eastern Africa.

The northern white is functionally extinct after decades of poaching and the wholesale loss of natural habitat.

There are two remaining females, kept under armed guard at a conservancy in Kenya, but neither animal is able to reproduce.

The last northern white male, named Sudan, died in 2018 .

Drawing on the expertise of fertility experts in Italy, the scientists have managed to create three precious northern white rhino embryos, ready to implant into a less-endangered southern white rhino.

What the experts do not fully understand, however, is how and when to implant these lab-made organisms into the uterus or womb of a surrogate mother.

This is where Karen comes in.

Our team watched as Dr Frank Goritz fired two sedative-laden darts just behind Karen's left ear and she stumbled to the ground after 20 or so minutes.

It is delicate work undertaken on a two-tonne creature.

"Anaesthesia is always dangerous for these animals, rhinos in particular," he said.

When Karen fell asleep, the scientists got to work.

Dr Thomas Hildebrandt isolated an embryo under a microscope while a colleague prepared the animal for the procedure.

A rhino's uterus is located five feet inside the animal's body and the only practical way to reach it is through the rectum.

It is a particularly difficult procedure to attempt.

Dr Hildebrandt said: "We have created so far three embryos from the northern white rhino but before we do the full procedure into a surrogate mother, we have to know that this system is working.

"It's a very important first step to prove that the embryo transfer is working."

Using a combination of high and low-tech equipment, Sky News watched the scientists move the embryo into the rhino's body through coils of plastic tubing a long and delicate needle.

A sophisticated 4D scanning machine was deployed to guide them as they worked.

There were moments of tension. The team lost the embryo on their first attempt but the microscopic organism was discovered in a plastic tube and they managed to implant it on their second try.

After the procedure, Dr Robert Hermes said they had every reason to be optimistic.

"We detected the first time that we were not in the right place," he said.

"It was difficult with the catheter (tube) to place the embryo because it is all about angling and little details, so we attempted it a second time and this time the catheter really went in very smoothly and we tried to put it very close to the ovary... and now it is up to her."

He said there were additional grounds for optimism out in the yard.

The team had used a sterile bull called Kimba to stimulate Karen before the procedure.

"The timing seems to be really good (because) the bull indicated that he was interested in her a couple of days ago... and if anybody knows he should know," Dr Hermes said.

There are limits, however, to the scientists' knowledge and expertise.

The two-tonne southern white rhino survived the IVF experiment, finding her feet after an unexpected snooze, but we have since learned from the team at the Leibniz Institute that the pregnancy has failed.

Dr Hildebrandt and team are unlikely to be deterred in their attempt to save the northern white, but it will a challenging and time-consuming process.