There have been several steppe bison mummies discovered, however, luck has shined on biologists as they found the best-preserved specimen to date. The Yukagir bison mummy was discovered with completely intact internal organs, Olga Potapova, collections curator and manager at the Mammoth Site of Hot Springs in South Dakota says.

A tribe in North Siberia stumbled across the frozen bison in 2011 and researchers have been performing numerous tests since then.

Potapova explains that such mummies are normally discovered as partial carcasses. This applies for most of North America’s or Siberia’s megafauna, which is most often eaten or destroyed despite having been in the permafrost for over tens of thousands of years.

“But the mummy was preserved so well that it [earned] a record for the level of its preservation.”

she added about the Yukagir bison mummy.

After analyzing the bison, scientists came to the conclusion that the animal died young, at approximately 4 years of age. According to Potapova, the animal died of starvation (there was no fat around the animal’s abdomen, supporting this claim).

“The exceptionally good preservation of the Yukagir bison mummy allows direct anatomical comparisons with modern species of bison and cattle, as well as with extinct species of bison that were gone at the Pleistocene-Holocene boundary,”

Evgeny Maschenko, co-author working at the Paleontological Institute of Moscow said.

Apart from the lack of abdominal fat, the bison was extremely well preserved. Its heart, circulatory system, blood vessels and digestive system were all intact although somewhat shrunk. The level of preservation was so good that scientists could obtain tissue samples from all of the bison’s organs.

The results are to be published in the Journal of Vertebrate Paleontology as well as presented at the Society of Vertebrate Paleontology’s annual meeting in Berlin.

Compared to America’s bison, this frozen mummy presented significantly larger horns as well as a second back lump. Stone Age cave art commonly features steppe bison similar to the frozen specimen. They are often shown being hunted by humans.

Researchers hope to use this discovery to gain insight on the species’’ behavior, on the bison’s cause of death and the cause of the steppe bison’s extinction.