The cave lion was one of the largest cats that ever lived, roaming a vast expanse of territory from Western Europe through Siberia to North America, hunting large prey (and perhaps even people) before becoming extinct around the end of the Ice Age.
New genomic research reveals what made this big cat unique and how it differed from the modern lion, its smaller cousin, although the two species interbred sporadically. The cave lion, whose scientific name is Panthera spelaea, became extinct approximately 14,000 years ago.
The researchers compared the genomes of 12 cave lions that lived between 17,000 and 148,000 years ago in places including Russia, Austria and the Yukon Territory in Canada with the genomes of 20 modern lions. Cave lion DNA was extracted primarily from bones and teeth, but also from soft tissue of frozen, well-preserved cubs from Siberia, where cold conditions helped preserve the . One of these females, named Sparta, is among the finest Ice Age specimens ever found.
“We showed that cave lions were not simply Ice Age versions of modern lions, but rather represented a highly distinct evolutionary lineage,” said evolutionary geneticist Love Dalén of the Center for Paleogenetics, a collaboration between Stockholm University and the Swedish Museum of Natural History, senior author of the study published in the journal Cell.
The study showed that the evolutionary lineages of the two species probably diverged around 1.7 million years ago, during the Pleistocene. Each species possessed unique genetic variants that likely adapted them to their different habitats and behaviors. These genetic differences were related to growth, vision, brain function and the development of the circulatory system.
The cave lion, which despite its name did not live in caves, was significantly larger and more robust than the modern lion. It inhabited colder climates, preferring the open grasslands and tundra of northern Eurasia and northwestern North America. This extinct ecosystem, called the mammoth steppe after its most prominent inhabitant, resembled today’s African savanna, but with frigid temperatures.
“The cave lion was undoubtedly an apex predator and as such played an incredibly important and impactful ecological role,” said evolutionary geneticist and lead author of the study, David Stanton of Cardiff University in Wales. “They were one of the most widespread carnivores that ever existed.”
Among their likely prey were woolly mammoths—most likely young or old individuals—as well as woolly rhinos, antelopes, reindeer, horses, and bison. Humans also inhabited these regions in the final stages of the Ice Age.
“Although there is no clear evidence that cave lions attacked humans, it seems very likely that they did so occasionally. Cave paintings show that Ice Age people were quite familiar with these animals. They are often depicted with remarkable accuracy and are usually shown without the large mane characteristic of modern male lions,” said Dalén.
Other predators that shared the landscape included wolves, cave hyenas, grizzly bears, and cave bears. The powerful saber-toothed tiger Smilodon was a more southern species, but may have come into contact with cave lions in the Yukon and Alaska regions during brief periods of Pleistocene climate warming.
The modern lion has not ventured as far north as the cave lion’s usual domain. But the study showed that the two species came into contact in , when the growth of continental ice caps and the expansion of steppe tundra drove cave lions south, causing their territories to overlap.
“Climate appears to dictate the level of interbreeding we observe between these species,” Stanton said.
The researchers said this interbreeding may have occurred in places like present-day Iran. That region was once home to a sizable population of modern lions, although they are now largely restricted to Africa.
Warming at the end of the Ice Age contributed to the extinction of many of the large Pleistocene animals, or megafauna, with human hunting another destabilizing factor.
“Cave lions, like the rest of the megafauna at the end of the Pleistocene, were under enormous pressure due to rapid climate change combined with increasing human population density. The extinction of cave lions fits into the general pattern we observed of megafaunal mass extinction at this time, but for reasons we still do not fully understand,” Stanton said.
