It's now hoped that artificial methods could be used to save the species

A dying northern white rhino is carrying the fate of his species with him - as conservationists pray for an unlikely miracle that he can father an offspring before passing away.

The world's only remaining male of his kind, 42-year-old Sudan is seeing out his final years under armed guard to safeguard him from poachers.

But with his back legs weakening and his sperm count lowering, the chances of Sudan being able to mount a female and sire more offspring diminishes daily.

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Sudan, a 42-year-old male northern white rhino, chews on grass next to one of his armed guards

The heavily armed security team provide 24 hour surveillance of the dying beast to protect him from poachers

The 42-year-old rhino's sperm count is diminishing, meaning he's increasingly unlikely to successfully breed

Rhino keeper Zacharia Mutai gives Sudan a scratch inside the animal's pen, located at a conservancy in Kenya

Richard Vigne, the chief executive of Ol Pejeta Conservancy, said: 'Sudan is quite an old animal as far as rhinos are concerned - he's an old animal and he's going to die soon, I think that's the reality.'

With breeding programs proving unsuccessful, the three-ton animal's death could mean extinction for the northern white rhino.

Sudan was born in South Sudan, but was caught in the Shambe region when he was just one-year-old and shipped to the Dvur Kralove Zoo in the Czech Republic.

In December 2009, he was moved to the Ol Pejeta Conservancy with two female northern white rhinos and another male, for a 'Last Chance To Survive' breeding program.

The other remaining male has now since passed away - meaning as the last remaining male in the world, the fate of the species rests solely on his shoulders.

Three of the five northern white rhinos left live at Ol Pejeta and it was hoped Sudan would be able to mate with the females Fatu, 15 and Najin, 25.

But so far all attempts have failed.

Mr Vigne said: 'It really came to a head with the death of Suni last year, the other remaining male northern white rhino - he was much younger than Sudan.

'These animals have been kept in captivity for a long time and there's been little success at breeding northern whites in captivity.

Richard Vigne (pictured), the chief executive of Ol Pejeta Conservancy, admits Sudan is likely to die soon

Rhino keeper Joseph Thuita gives Sudan a kiss behind the ear while taking care of him at the conservancy

'Sudan is 42-years-old and the quality of his sperm is not particularly great. His ability to mount a female is almost non-existent because of his problems with his back legs.

'It was always going to be a shot in the dark. We had the last remaining potentially reproductively viable northern whites left in the world and to recover a species from that level was always going to be a long shot.'

The majestic animal is under guard 24-hours-a-day to protect him from poaching, and his horn has been filed down to further lower the risk of attack.

But the rare rhino has formed a strong bond with his gun-carrying guards and keepers.

Keeper Zacharia Mutai said: 'Sudan loves to be rubbed under the belly, and scratched behind the ears, it makes him feel relaxed. When we call his name he often comes to us.

'He's really calm because he's used to us, but animals are unpredictable they can charge and they can attack, so even I have to be careful.'

Rhino keeper Joseph Thuita poses for a photograph at the conservancy where three of the five remaining northern white rhinos live

Armed guard John Mugo spends his days in the paddock with the rhinos, carrying a G3A3 assault rifle.

He said: 'Sudan is special because he's the last one of his kind surviving in the whole universe. We guard Sudan 24-hours a day around the clock to protect him from poaching.

'He's under threat because of his horn, we use guns to ensure the security of the rhinos.'

The guards change shift at 6am in the morning and 6pm at night, ensuring the endangered animals are protected at all times.

But Mr Vigne believes there is still hope for the northern white rhino species.

With the rhinos failing to reproduce naturally, he believes artificial methods could still save it.

The team are now looking at using southern white rhinos as surrogates to carry northern white fertilised eggs to create a pure bred northern white calf.

'The problem with that is the technology to do it is yet to be developed in rhinos, so we have to develop the technology and the ability to do it with rhinos before we try to do it on the last remaining northern whites,' he explained.

Another option is artificially inseminating southern white rhinos to create cross-bred offspring.

Whilst Mr Vigne admits the current population of northern white rhinos could die out - he believes developments in science will bring them back from extinction in the future.

'The chances are the living animals that we have on the planet today will die off and disappear before we are able to develop the techniques to recover the species.

'But we'll have preserved enough of the genetic material that in the future we could create calves and live animals on the ground.

'There's quite a few cell cultures from the various different rhinos that have existed in zoo conditions which are now in storage.

'In time, when the science allows it - we could create egg and sperm cells to create an embryo for implantation in a southern white. It's a scientific process referred to as de-extinction.'

Guard John Mugo poses for a photograph as Sudan roams the paddocks behind him

While the current population of northern white rhinos could die out, developments in science may bring them back from extinction in the future

Although the rhinos have failed to reproduce naturally, their keepers believe artificial methods could still save the species

Like all rhinos, northern white rhinos have been hunted for their horns. Sudan's (pictured) has been filed down in an attempt to reduce his value to poachers

Sudan was born in South Sudan, but was caught in the Shambe region when he was just one-year-old and shipped to the Dvur Kralove Zoo in the Czech Republic

It wasn't until 2009 that Sudan (pictured) was moved to the conservancy for the 'Last Chance to Survive' breeding programme

Sudan chews on some plants while he is patted by rhino keeper Zacharia Mutai at his home in Kenya

As late as 1960 there were more than 2,000 northern white rhinos in the world, but their numbers have drastically declined due to poaching

Ol Pejeta Conservancy is desperately trying to raise funds to ensure the future of the northern white rhino

According to the World Wildlife Fund as late as 1960 there were more than 2,000 northern white rhinos in the world - but intense poaching has brought the sub-species to the brink of extinction.

'Humans are 100 per cent to blame for what's happened to rhino populations across the planet,' Mr Vigne said.

'Like every rhino, the northern whites face demand for their horn. As demand has increased the incentive for people to kill rhino to supply horn has increased.

'The northern whites we have here are semi-domesticated, they're used to humans and therefore they're easily approachable.

'There's huge incentive for poachers to kill rhinos illegally, and because their approachable we protect them closely to prevent poaching. Rhino horn is worth more than cocaine in the Far East.'

Ol Pejeta are trying to raise funds to ensure the future of the northern white rhino. Funding the artificial breeding programme could cost between $1million and $4million.

Click here to contribute to the campaign to help save the northern white rhinoceros