One of the largest felines to ever roam the Earth, the formidable cave lion once dominated a vast territory stretching from Western Europe across Siberia and into North America.
This apex predator, which hunted large prey and potentially even humans, vanished around the close of the Ice Age approximately 14,000 years ago.
New genome research now offers unprecedented insights into what made this magnificent big cat unique, distinguishing it from its smaller, modern lion cousin, despite evidence of sporadic interbreeding between the two species.
A study, published in the journal Cell, compared the genomes of 12 cave lions, dating from 17,000 to 148,000 years ago, found in locations such as Russia, Austria, and Canada’s Yukon territory, with those of 20 modern lions. Genetic material was primarily extracted from bones and teeth, though remarkably preserved soft tissue from frozen Siberian cubs, including a female named Sparta, also provided crucial DNA.
“We show that cave lions were not simply Ice Age versions of modern lions, but instead represented a highly distinct evolutionary lineage,” stated evolutionary geneticist Love Dalén of the Centre for Palaeogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History, and a senior author of the study.
The research indicates that the evolutionary paths of the two species diverged roughly 1.7 million years ago during the Pleistocene Epoch. Each developed unique genetic adaptations suited to their respective habitats and behaviors, with differences observed in genes related to growth, vision, brain function, and circulatory development.
Despite its name, the cave lion, or Panthera spelaea, did not actually inhabit caves. It was significantly larger and more robust than the modern lion, thriving in the colder climates of the open grasslands and tundras of northern Eurasia and northwestern North America. This now-vanished ecosystem, known as the mammoth steppe, shared similarities with today’s African savanna but was characterized by frigid temperatures.
“The cave lion was absolutely an apex predator, and as such filled an incredibly important and impactful ecological role,” said evolutionary geneticist and study lead author David Stanton of Cardiff University in Wales. “They were one of the most widespread carnivores to ever live.”
Its probable diet included woolly mammoths, likely targeting young or elderly individuals, as well as woolly rhinoceroses, antelope, reindeer, horses, and bison. While humans also lived in these regions during the later stages of the Ice Age, direct evidence of predation is scarce.
“While there is no clear evidence that cave lions preyed on humans, it seems highly likely that they occasionally did so,” Dalén noted. “Cave paintings show that Ice Age people were highly familiar with these animals. They are often depicted with remarkable accuracy, and are usually shown without the large mane characteristic of modern male lions.”
Other formidable predators sharing the landscape included wolves, cave hyenas, brown bears, cave bears, and the scimitar-toothed cat Homotherium. The powerful saber-toothed cat Smilodon, a more southern species, may have encountered cave lions in the Yukon and Alaska during brief periods of Pleistocene climate warming.
Modern lions typically did not venture as far north as the cave lion’s domain. However, the study revealed that the two species did come into contact during particularly cold stretches of the Ice Age. Expanding continental ice sheets and the spread of the steppe tundra pushed cave lions southward, causing their ranges to overlap.
“Climate appears to dictate the level of interbreeding that we see between these species,” Stanton explained, suggesting that such interbreeding may have occurred in regions like modern-day Iran.
The warming climate at the end of the Ice Age played a significant role in the extinction of many large Pleistocene animals, or megafauna, with human hunting presenting another destabilizing factor.
“Cave lions, like the rest of the megafauna at the end of the Pleistocene, were under a huge amount of pressure due to rapid changes in climate combined with increasing human population densities,” Stanton concluded. “The extinction of cave lions falls into the general pattern that we see of mass extinction of megafauna at this time, but for reasons that we don’t completely understand.”
