The ancient puppy still has its own teeth, and its brain is also thought to be intact.
Experts are examining whether the young animal was a "pet", while controversial South Korean cloning guru Hwang Woo-suk - present at a remarkable autopsy of the extinct Pleistocene canid - has taken samples in a bid to bring the extinct species back to life.
A video shows how mud and dirt from a dozen millennia was washed off the frozen puppy ahead of a post mortem on the animal in Yakutsk, capital of Russia's Sakha Republic, where the mummified remains were found on a steep bank of River Syalakh.
The puppy was found to be well preserved, including the brain, reported The Siberian Times, which revealed the pictures and video from the procedure.
Russian expert Dr Pavel Nikolsky, research fellow of the Geological Institute, Moscow, said: "The carcass is preserved really very well.read more=http://www.mirror.co.uk/news/weird-news/puppy-frozen-time-12400-years-7565134