No meteor from outer space, no unstoppable pandemic, no heroic, ultimately futile last stand. Instead poor sperm, weak knees and ovarian cysts mark the end of a lifeline cut short by human greed, ignorance and indifference.
With just five northern white rhinos left on earth, the animal's end is inevitable.
Scientists and conservationists hope that advancements in genetics and in vitro fertilisation might allow for its test tube resurrection in the future, but before that the northern whites will die, one by one, over the next few years.
"We are down to five, so they are very close to extinction, perhaps in a few years," said Jan Stejskal of the Dvur Kralove Zoo in Czech Republic which, thanks to acquisitions in the 1970s, owns all the remaining northern whites.
"I still believe there is a hope we will be able to save them. The best we can do now is harvest sperm and egg samples for future in vitro fertilisation, and wait until the time the techniques are developed enough to give us a good chance of reproduction," said Stejskal.
The last living male, named Sudan, is found on a 90,000-acre (36,400-hectare) reserve of savannah and woodlands in central Kenya, along with two of the remaining females. The other two females live alone in zoos in the Czech Republic and the US. Two further males -– Angalifu and Suni -– died last year.
At 43, Sudan is elderly by rhino standards and vets say his sperm is low quality. Nola at San Diego Zoo is also beyond reproductive age while Nabire at Dvur Kralove Zoo is 31 but suffers from ovarian cysts. In Kenya, Najin, 25, cannot mate because of her weak hind legs, while her daughter Fatu, 14, is infertile.
- No sex drive -
The Ol Pejeta rhinos were shipped from Dvur Kralove in 2009 in the hope that the natural environment would encourage breeding. That hope has faded.
"Were these free-ranging animals out in the wild they would breed just fine, but they were old animals, they came from a zoo and you don't have a normal social situation," said Dr Peter Morkel, a vet and rhino expert at conservation group Back to Africa.
"There were a number of matings and at one stage we were pretty sure Fatu was pregnant," said Morkel. "I think we got pretty close."
Fatu, the most recently born northern white rhino, will likely be the last.
"We are going to witness the demise of this species, that’s the reality of what we face. They are going to die here," said Richard Vigne, Ol Pejeta’s chief executive.
"It is an indictment of what the human race is doing to planet earth and it's not just happening to rhinos. It's happening to all sorts of species, big and small, across the planet," said Vigne, lamenting decades of inaction.
Scientists call the mass wiping out of species by humans the "Sixth Great Extinction" -- the fifth being the one that killed off the dinosaurs 65 million years ago. The northern white rhino's extinction is unusual only because it is such a large, recognisable animal.
"The northern white's geographic range was Central Africa and subject to war, strife and lawlessness and that opened the door for poachers to kill them at will. People are absolutely to blame," said Vigne.
Modern rhinos have plodded the earth for 26 million years. As recently as the mid-19th century there were over a million in Africa. The last northern whites disappeared from the wild a decade ago and will soon follow the western black rhino, declared extinct in 2011.
- Armed guards for the final few -
Assisted reproduction may yet bring the northern white back but if they cannot be reintroduced into the wild then, some ask, what is the point?
"If they're just to become museum specimens in zoos then it's perhaps time to see them go,” said Dr Rob Brett, regional director for Africa at Fauna and Flora International.
Against all the evidence, park ranger Mohammed Doyo -- who looks after Sudan, Najin and Fatu -– clings to the forlorn hope that they will reproduce naturally.
When Doyo talks the rhinos listen, backing away from nervous visitors unsettled by the huge animal's closeness, or returning to their pens to rest or lumbering slowly towards their food.
"To lose such an animal will be like losing a child," he said. A few feet away, Fatu munched her way through a four kilogramme pile of carrots and bananas that Doyo had dumped on the ground.
To deter poachers the northern whites are escorted by armed wardens at night and their horns are trimmed back to uneven stumps. The horns are worth more than $65,000 a kilo on the Asian black market, and sought after by consumers who are falsely convinced that the ground-up keratin -- the same substance as human fingernails and toenails -- contains powerful medicinal properties.
Ol Pejeta is also home to nineteen southern white rhinos and 105 black rhinos which roam freely across a 700-acre enclosure.
At dawn one recent morning a group of three southern white rhinos snuffled and grazed at the foot of a tree as, behind them, the sun rose above the jagged peaks of Mount Kenya. They stood quietly for a while and then, realising they were being watched, trudged slowly into the distance.