The remote and icy north of the Yakutia Republic in Siberia has become well-known for the discovery of remains of Ice Age mammals within its thick permafrost deposits.
In some cases, entire buried carcasses that have been shrunken and desiccated down to a natural mummified state have been dug up.
Such finds can help scientists answer key questions about extinct species, the conditions in which they lived and their relationships to other species including animals alive today.
Here are four mummies that have given us hints about what it was like to live through the Ice Age.
The Yukagir bison
Standing 2 metres tall at the shoulders with large horns curving outwards at the tip, the steppe bison (Bison priscus) must have been a formidable foe for Ice Age human hunters.
The bison was found in a sleeping pose with no signs of injury
Members of the Yukagir tribal community discovered the remarkably well-preserved and complete remains of a male steppe bison in Yakutia in August 2011. It is believed to be in better condition than the other two known complete specimens. Radiocarbon dating of horn and hair samples suggests it lived around 10,500 years ago.
Gennady Boeskorov of the Russian Academy of Sciences, in Yakutsk and his colleagues estimate the bull weighed in at 500-600 kilograms and was 1.7m tall at the shoulder blades. It was found in a sleeping pose with no signs of injury, so is believed to have died of natural causes. Pollen discovered in its stomach show it ate grasses and wild herbs. DNA analysis will help scientists understand the relationships between different species of ancient bison and modern North America bison.
The steppe bison lived in northern Europe, Asia and North America, mostly during the Pleistocene between two million and 11,700 years ago. It was a little larger than today's American bison, with bigger horns and a second hump on its back. Several examples of Stone Age cave art feature the species, including a scene at Villars in France in which a wounded bison is goring a fallen hunter.
The Kolyma woolly rhinoceros
Woolly rhino remains have been discovered as far west as the British Isles and as far east as the Chukotka Peninsula, the eastern tip of Siberia. They are believed to have been one of Eurasia's most abundant large mammals. However, we have only found the remains of a handful.
The rhino's short legs may have struggled with an increase in deep snow
In 2007, gold miners discovered the well-preserved frozen remains of a female woolly rhino at the opening of a gold mine in Yakutia.
Boeskorov, who studied the mummified carcass, estimated it is likely to have weighed around 1.5 tons. The rhino had thick brown fur and skin, a short, fur-covered tail and narrow ears of the same shape as those depicted in cave paintings. It lived around 39,000 years ago.
While the rhino was well-adapted for icy cold conditions, its short legs may have struggled with an increase in deep snow caused by the higher temperatures of the late Pleistocene and early Holocene, Boeskorov believes.
The Selerikan pony
Gold miners also came across two legs and a tail belonging to a mummified pony sticking through the roof of a tunnel they were digging nine metres below frozen ground near the upper Indigirka River, in Yakutia, in 1968. Experts from the Zoological Institute in St Petersburg were able to recover most of the body except the head.
It was found to be a Przewalski’s horse (Equus przewalskii), a wild horse only nowadays found in Mongolia.
Known as the Selerikan pony, the mature stallion lived between 35,000 and 39,000 years ago, and probably died at the age of seven or eight.
Its gastrointestinal tract was full, suggesting it died a quick death. Stomach content analysis identified grasses, sedge, herbs and woody plants as being part of its diet. The position in which the carcass was found, with its hind legs pointing down and more horizontal forelegs, led scientists to conclude the pony had died after becoming stuck in a bog.
The Yuka mammoth
Here's an idea: some ancient human hunters used lions to catch wild animals before moving in to claim their prey. There is no proof, but there is some circumstantial evidence, in the form of marks on the body of a young female mammoth.
A long straight cut and marks in a "repeating ladder pattern" could have been made by human tools
Yukagir tribe members found the corpse on the coast of an area called Oyagossky Yar in Yakutia in 2009. Dubbed Yuka after its finders, its skin and some of its strawberry-blonde fur are well-preserved, as are a lot of mummified muscles and ligaments. Unusually, its trunk is intact.
Research suggests the animal was 8 to 10 years old when it died, stood no more than 165cm tall at the shoulders, and lived 39,000 years ago. Before the discovery, nobody knew what mammoths were like at this stage of development. The researchers were surprised to see the beginnings of tusks that had not yet broken through the skin.
The markings are unlike any made by any known stone tools
Yuka had unhealed cuts and scratches that suggest it was attacked by a large predator, probably a cave lion, shortly before its death. However, they are thought not to have penetrated enough to have caused its death. Meanwhile, a long straight cut and marks in a "repeating ladder pattern" could have been made by human tools.
So Daniel Fisher of the University of Michigan in Ann Arbor has suggested the human-like marks were made by human hunters who had moved lions off a kill. There is precedent: members of the Dorobo tribe in Kenya still get meat by stealing kills from lions.
If the marks are confirmed to have been made by hunters, it would be the first evidence of interaction between ancient humans and mammoths in this part of the world. However, the markings are unlike any made by any known stone age tools, so other researchers think they may have been made more recently.