28,000-Year-Old Cave Lion Cub Found Perfectly Preserved in Siberian Permafrost

In 2017 and 2018, local mammoth tusk hunters made an incredible discovery on the banks of a Siberian river: two ice-age cave lion cubs lying only 15 meters (approximately 49 feet) apart.

The two cubs, a male named Boris and a female named Sparta, are remarkable because of what they can tell us about Ice Age cave lions, and especially because of the condition Sparta was found in.

“Sparta is probably the best preserved Ice Age animal ever found and is more or less undamaged apart from the fur being a bit ruffled,” study co-author Love Dalén, a professor of evolutionary genetics at the Centre for Palaeogenetics in Stockholm, said in a Stockholm University press release. “She even had the whiskers preserved.”

Paleontologist Dr Victoria Heritage of the Natural History Museum in London investigates the 28,000-year-old cub

The pair were first thought to be siblings. But as the first major study to be published on the pair concluded this week, they lived more than 15,000 years apart; carbon dating put Boris at 43,448 years old. A CT scan and genetic tests also determined the younger of the two was female: hence her new name, Sparta.

Cave lions have been extinct for around 14,000 years. The team that later went to cover the excavation, which comprised top palaeontologists from Russia, Sweden, Japan, the US and the UK, could barely believe their eyes.

“It was absolutely stunning,” Love Dalén said, “You know you might find something, but this looked like it had died just two days ago.”

Parts of the permafrost had already melted around Sparta, he said, but nevertheless the team had to be “very careful” removing the specimen from the cave, cleaning away some of the mud before putting her on a stretcher.

Sparta, an Ice Age cave lion believed to be 28,000 years old

The pair arrived in Yakutsk in November 2018 and January 2019 and were rigorously tested for infectious diseases, including anthrax, that can lie dormant for millennia before being scanned to investigate the condition of their bones and soft tissue.

The newly-published study found both cubs were just one to two months old when they died. There was no sign they had been killed by a predator, suggesting they might have fallen and become trapped, or been buried in a mudslide.

It also yielded some important clues about the evolution of the Eurasian cave lion. Both cubs’ golden coats were similar to those of today’s African lion cubs, but with a long, thick fur undercoat that could have insulated them from the cold.

Scientists also found their teeth had come through at an earlier age than would be expected of African lions today, suggesting that because of the harsher winters “cubs had to develop faster and be able to eat meat at a younger age”.

A full “autopsy” to examine discrete aspects like the contents of the cubs’ stomachs as well as full genetic sequencing may take place in future. For now, Prof. Dalén says, “This particular paper was a lot of fun. It was a great collaboration between scientists.”