V/O: 29-year-old Jackson is a very special bull elephant. He produces the most fertile semen in America.
V/O: It's Thomas Hildebrandt and Robert Hermes's job to get hold of it. But one false move could end in disaster.
THOMAS HILDEBRANDT: Every elephant bull is dangerous. They are not pets, they are bulls.
THOMAS HILDEBRANDT: So if you are coming in his way he will deal with you.
V/O: Thomas and Robert are applying the know-how developed to assist human reproduction to save species at the brink of extinction. They're the world leaders in the art of animal manipulation.
V/O: To collect semen from Jackson, Thomas will have to stimulate the bull elephant. But not where you might expect.
ROBERT HERMES: An ejaculation in the elephant he can trigger by massaging the prostate and the best way to get to the prostate is through the rectum.
ROBERT HERMES: Penile massage does not work, it's even counterproductive. There is a zone on the penis which if you touch it the elephant starts to flick with the penis that can even knock you off your feet, because it is such a strong movement.
INTERVIEWER: Have any of your colleagues suffered from that?
ROBERT HERMES: There is a famous colleague who got a black eye from penis banging.
V/O: An elephant penis needs to be 1.5m long if it's even to stand a chance of reaching the vagina.
THOMAS HILDEBRANDT: Semen comes already.
INTERVIEWER: So was that quite hard work then?
THOMAS HILDEBRANDT: It was quite a hard workout. If I sweat blood then we get semen.
V/O: Thomas has to hand-carry the semen to the female elephant who is waiting on the other side of America in Salt Lake City.
Inseminating 20 year old cow elephant Christy is going to be a marathon task. They have to navigate one metre inside the elephant before arriving at three tiny holes. The one in the middle is the vagina, the other two are dead ends.
THOMAS HILDEBRANDT: The dimensions are only 2mm to 4mm, extremely small, and if you haven't got the right angle then you can't get in.
V/O: Finally, they're through and Jackson's semen is injected into Christie's cervix.
THOMAS HILDEBRANDT: The semen was good, the placement was good, and so far she looks healthy inside. Hopefully she will have a little baby from Jackson.
V/O: For Thomas these inseminations are part of a war he has been fighting for the past 15 years.
V/O: The planet's creatures are now facing the biggest mass extinction since the dinosaurs were wiped out. Species are currently disappearing at up to 10,000 times the natural rate.
V/O: There are thought to be only 13 northern white rhinos left in the world, almost everybody has given up on saving them. Thomas and his team are their last chance of survival.
ROBERT HERMES: These are the last of their kind. They are going extinct and we are just very lucky to be able to work on this species to try to prevent that extinction.
ROBERT HERMES: We have now stimulated the penis to a very nice size. You can see the wings that unfold in the vagina, so the penis stays inside. It's a very fantastic anatomical feature. And the tip of the rhino penis screws into the cervix of the female.
V/O: Fatu is the youngest and healthiest female of her kind left on the planet.
V/O: She has been injected with hormones to help her ovulate. Using the latest ultrasound technology Robert is examining the ovaries, looking for signs that the treatment has worked.
ROBERT HERMES: Thomas, Thomas, Thomas, Thomas! The follicle is so big that it seems that she is going to ovulate tonight.
V/O: They're going to have to inseminate straight away, as Fatu can only be kept under anaesthesia for another 15 minutes.
THOMAS HILDEBRANDT: We have to rush now.
ROBERT HERMES: We are very excited. We have to rush.
THOMAS HILDEBRANDT: It takes the male more than one hour to reach the same position which we have now to get in five minutes.
ROBERT HERMES: Getting through the structures takes a lot of knowledge and skill as well. Thomas's skill.
V/O: Finally he gets there. And they just manage to finish the insemination within the 15 minute deadline.
THOMAS HILDEBRANDT: It's exhausting, but now we have to leave.
INTERVIEWER: Do you think you put the sperm in the right place?
THOMAS HILDEBRANDT: Yes, we put it in the right space. The hormone profile with tell us in three months if we were successful or not.
V/O: Even when numbers drop to just a handful of animals it's still possible to save a species.
V/O: In 1977, North America's only native ferrets were facing extinction. JoGayle Howard discovered the problem: 50 per cent of the male ferrets were not mating.
JOGAYLE HOWARD: The black footed ferrets got down to 18 animals. We really needed every animal to get represented in this very small population, so we decided to develop the artificial insemination for black footed ferrets to save the species.
V/O: Thanks to artificial insemination the black footed ferret population has grown from just 18 to thousands.
V/O: After a nail-biting wait, Thomas and Robert finally receive the pregnancy test results. Fatu the rhino didn't get pregnant. And neither did Christy the elephant.
ROBERT HERMES: Despite the setback we have to continue. We are very determined. We know that the work we do is very important and we are at the brink of the extinction of a species here. Everybody has to keep it going.