An autopsy on one of the cats will take place in Yakutsk later this year

Russian scientists believe two ancient lion cubs dug from the Siberian permafrost are likely to show traces of the world's oldest mother's milk.

Frozen for at least 12,000 years, the researchers have 'reason to believe' the carcasses of the extinct predators contain breast milk dating back to prehistoric times.

An autopsy on one of the infant big cats will take place in the city of Yakutsk later this year with the 'hope' of confirming the sensational discovery.

Frozen for at least 12,000 years, researchers have 'reason to believe' the carcasses of extinct lion cubs (one pictured) contain breast milk dating back to prehistoric times. An autopsy on one of the infant big cats will take place in the city of Yakutsk later this year with the 'hope' of confirming the sensational discovery

'Experts do not want to draw premature conclusions but they have "reason to believe" the well-preserved innards of two cave lion cubs - one of which will be subjected to an autopsy, the other preserved for future study - contains an opaque white fluid that will prove to be from an extinct lactating lioness,' reportedThe Siberian Times.

The other cub will be kept in the hope that future scientific advances will allow experts to understand more about a species that was once present on the Eurasian land mass from the British Isles to the extreme east of Russia.

The cubs were dug last year from their icy grave 'complete with all their body parts: fur, ears, soft tissue and even whiskers', said Dr Albert Protopopov, head of the mammoth fauna studies department of the Yakutian Academy of Sciences.

It was recently reported South Korean cloning guru Hwang Woo-suk took samples from the cub that will be subjected to the autopsy.

He is also hoping to clone the extinct woolly mammoth.

Skin and muscle tissue was extracted from the ancient creature's remains, aiming to find living cells, which could trigger research aiming to bring the extinct cave lions back to life.

The perfectly preserved predators (pictured) were found around 650 miles from the Siberian capital of Yakutsk. Experts said they not want to draw premature conclusions but have "reason to believe" the well-preserved innards of the cubs contains a white fluid that will prove to be from an extinct lactating lioness

CAVE LIONS OF SIBERIA The European or Eurasian cave lion is an extinct species, known from fossils and prehistoric art. It's most closely related to the modern lion and ranged from Europe to Alaska over the Bering land bridge until the late Pleistocene, around 10,000 years ago. An adult European cave lion is thought to have measured 3.9ft (1.2metres) tall and 6.9ft (2.1metres) in length without its tail, based on a skeleton found in Germany. This means it was a similar size to a modern lion. It's thought the lions probably hunted larger herbivorous animals of their time, including horses, deer, reindeer, bison and even injured old or young mammoths. No-one knows why the lions became extinct, but one suggestion is the population of cave bears and deer - one source of prey - caused them to die out. Advertisement

A sudden summer rise - then fall - in the level of the Uyandina River led to cracks appearing and local worker Yakov Androsov spotted an ice lens with the lion cubs inside.

Dr Protopopov said last year when he unveiled the animals to the media: 'Comparing with 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.'

He thinks they may have perished after the lioness hid her cubs in a cave to protect them from hungry lions.

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.

Cave lions lived during Middle and Late Pleistocene times on the Eurasian continent, from Britain to the extreme east of Russia.

They also roamed Alaska and north western Canada.

Research on the two cubs could help to explain why the species died out around 10,000 years ago, said experts.

Research on the two cubs could help to explain why the species died out, 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.

The discovery was made in the Sakha Republic, otherwise known as Yakutia (shaded in red) and scientists believe the two cubs are the best preserved ever found

Experts have said the 'perfectly preserved' predators, named Uyan and Dina, are a 'sensational find'. An adult European cave lion is thought to have measured 3.9ft (1.2metres) tall and 6.9ft (2.1metres) in length without its tail, based on a skeleton found in Germany

Research on the two cubs (pictured) could help to explain why the species died out around 10,000 years ago, say experts. Cave lion fossils have also been found in Alaska and Canada. Remains are rare, making the recent find particularly exceptional, and only fragments of carcasses and skeletons have been found before

Remains are rare, making the recent find particularly exceptional, and only fragments of carcasses and skeletons have been found before.

The discovery will give scientists a better idea of what the animals that once roamed Yakutia looked like.

Until now, their impressions were based on a handful of skulls, teeth and bones found in the freezing region.

Cloning expert Hwang Woo-Suk visited Yakutsk earlier this year to watch over scientists as they removed samples of skin and muscle tissue from a young cave lion. He plans to clone the animals using these samples

The European or Eurasian cave lion is an extinct species, known from fossils and prehistoric art. Cave lions (remains of one of the cubs is pictured) lived during Middle and Late Pleistocene times on the Eurasian continent, from Britain to the extreme east of Russia

Careful study of the remains may help explain why prehistoric cave lions became extinct.

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

In 2006, Hwang was dismissed by Seoul National University for faking groundbreaking work in stem cell research.