Today in Yakutsk, the coldest city on Earth, the pre-historic specimens were revealed to the media in a permafrost cave, perhaps reminiscent of their natural habitat when they roamed Siberia. Picture here and below: Vera Salnitskaya

The ancient cubs, called Uyan and Dina, the best-preserved ever seen of this long-gone species, are a 'sensational' find, according to scientists who normally choose their adjectives with studied caution.

Today in Yakutsk, the coldest city on Earth, the pre-historic specimens were revealed to the media in a permafrost cave, perhaps reminiscent of their natural habitat when they roamed Siberia.

They were displayed on giant slabs of ice, the size of plump domestic cats. The permafrost preserved them in wondrous lifelike detail for at least 12,000 years but they could be even more ancient: only now will tests commence to establish their true age.

The permafrost preserved them in wondrous lifelike detail for at least 10,000 years.

The cubs were found in Abyisky district, on the bank of the Uyandina River,' said Dr Albert Protopopov, head of the mammoth fauna studies department of the Yakutian Academy of Sciences.

There was a summer rise in the river level, and when the water subsided there were landslides and cracks. Worker Yakov Androsov said: 'In one crack, we saw an ice lens with some pieces inside. We decided to take a closer look and found the cubs.'

The river is just below the Arctic Circle, some 1,045 kilometres north east of regional capital Yakutsk. 'This find, beyond any doubt, is sensational,' said Protopopov. The cubs 'are complete with all their body parts: fur, ears, soft tissue and even whiskers'. They are, he claimed, unique in the world, the most complete remains of cave lions ever found.

The cubs were the size of plump domestic cats.

Might it be possible to clone the cave lions? The scientists were not ready to discuss the issue, although there are plans to use DNA found in remains of ancient, extinct woolly mammoths in the same region to bring the beasts back to life. 'I would not talk about cloning now. Our main task here is to decipher the genome and to work with it. I think that speculation about cloning is very premature.'

Yet these cave lions are, he claimed, unique in the world, the most complete ever found.

Worker Yakov Androsov, who found the cubs (top). Yakov Androsov(right) poses with Vasily Gorokhov(left), who found mammoth Yuka.

The Siberian Times revealed the existence of the lion cubs last month, provoking interest from around the world. Yet today is the first time the remains of these ancient creatures have been widely seen, revealed by Russian scientists more familiar with discovering the relics of the extinct woolly mammoth.

'Possibly, the cubs died in a hole, in a landslide, and afterwards this site was never affected by weather,' said the academic. 'This is how we explain such unique preservation of the animals.'

'Possibly, the cubs died in a hole, in a landslide, and afterwards this site was never affected by weather.'

Dr Protopopov said: 'Comparing with the modern lion cubs, we think that these two were very small, maybe a week or two old. The eyes were not quite open, they have baby teeth and not all had appeared.

'We do not know the gender, but we will give them the names in honour of Uyandina river, where they were found, that is Uyan and Dina assuming one is male and other female. Yet we have options for two females - Uyana and Dina, or two males - Uyan and Din.'

Further research will include an MRI scan, and radiocarbon dating probably at the University of Groningen in the Netherlands. But the Siberian team wants to find and co-operate with a world renowned expert of lion cubs.

Albert Protopopov: 'This find, beyond any doubt, is sensational.'

Scientist Dr Gennady Boeskorov said: 'The main complexity of our task is that here we have not adult lions, but cubs, so we are searching for the specialists experienced in the research of cubs. It's interesting to see the adaptive mechanisms, which helped them to survive in the cold. They definitely differed from the modern lions, and we think there should be something that allowed them to adapt to the climate.'

Dr Protopopov said: 'We suppose that the cave lioness behaved like the modern lioness in pride,' he said. 'It seems like she gave birth to the cubs and hid them in cave or hole to protect from the hungry lion. Then the landslide covered it and they remained surrounded in permafrost. Also the air intake was blocked, and this helped their preservation.'

Dr Gennady Boeskorov said: 'The main complexity of our task is that here we have not adult lions, but cubs.'

Next year researchers will go back to the site and search for remains of possibly one more cub, or even the lioness.

The remote region where the lions were found, known as Yakutia or the Sakha Republic, is the largest in the Russian Federation. The cave lions became extinct round 12,000 years ago.

Cave lions - Panthera spelaea (Goldfuss) - lived during Middle and Late Pleistocene times on the Eurasian continent, from the British Isles to Chukotka in the extreme east of Russia, and they also roamed Alaska and northwestern Canada. Finds of their remains are rare, and the Yakutian scientists have no hesitation in saying that this pair are best preserved ever unearthed in the world.

The cubs were found in Abyisky district, on the bank of the Uyandina River, in 57 kilometres from Belaya Gora village.

After the ice lions were found, tests were conducted to ensure they did not carry ancient diseases: but they were given the all clear. Research on the two cubs could help to explain why the species died out around 10,000 years ago, since the animal had few predators, was smaller than herbivores, and was not prone to getting bogged down in swamps, as did woolly mammoths and rhinos.

One theory is a decline in deer and cave bears, their prey, caused their demise.