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The Ice Age was a friendly time for large mammals. From about 2.5 million years ago to 11,700 years ago, they had space and time to roam far. For example, lions were once found all over the world.Evolved in East Africa, Big cats padded through Europe and Asia, eventually making their way to North America via Beringia, the now-submerged continent that once connected Siberia, Alaska, and the Yukon.
Lions roamed North America for tens of thousands of years before becoming extinct. Today, there are no lions lounging in the rapeseed fields of southern Alberta or chasing prey in the grasslands of the Yukon.
Cave lions and their larger relatives, American lions, first entered North America during the last ice age towards the end of the Pleistocene. Already part of the European landscape, humans have painted and sculpted portraits of these giant lions in caves, including the famous Chauvet Cave in France.
Julie Meechen, a vertebrate paleontologist at Des Moines University in Iowa who specializes in big cats and other mammalian carnivores, said the art in the cave is a reflection of how these lions look and feel. He says he has provided scientists with information about how he lived. Cave paintings depict large reddish-haired, maneless lions living in groups.
Fossil evidence also suggests that, like modern African lions, Pleistocene males were considerably larger than females, Meachen explains. A male American he notes that the maximum size of a lion is about 420 kilograms, while the current lion weighs only 270 kilograms. “They could probably kill whatever they wanted to kill. [male] Mammoth,” she says.
Alexander Salis, a postdoctoral fellow in vertebrate sciences at the American Museum of Natural History in New York, said: A closer look at the story of the North American lion As part of a study at the University of Adelaide, Australia. Working with Miechen and his team of colleagues, Salis analyzed the mitochondrial DNA of his 39 Pleistocene lions from North America and Eurasia. He has found that lions have migrated to North America on at least three separate occasions. However, their adaptability waned in the face of changing climates and habitats.
Each wave of lion migration appeared to correspond to changes in global climate and sea levels, Salis explains. As the planet fluctuated between freezing and thawing, sea levels rose and fell, exposing and flooding Beringia many times. During the Ice Age, expanding ice lowered sea levels, opening up routes to North America that lions took advantage of, bringing DNA markers that reveal where and when each one came from.
The first lions to set foot in North America about 165,000 years ago were of the cave lion breed. Salis explains that when Beringia was flooded during the warmer months, the lions were cut off from the Asian population and evolved into the lions of America. American lions didn’t spend much time in the north, instead making their way to what is now the United States, he says. Nearly all mountain lion fossils have been found south of the ice sheet that once covered most of the continent. Except for one 67,000-year-old specimen of his found at a Yukon site. Salis has confirmed that this is the oldest known American lion.
About 63,000 years ago, Salis said, a second wave of cave lions invaded eastern Beringia (now Alaska and the Yukon). For some reason, these cave lions stayed on top of the ice sheets and remained separate from the American lions that had already dispersed southward. It became clear that
The extinction of cave lions in eastern Beringia may be due to warming trends in the region, Salis says. Sea levels have risen and humid weather has arrived. This is a key component of peat growth. The expansion of peatlands in eastern Beringia has fragmented habitats and altered vegetation, greatly impacting herbivores, causing cave lions and other carnivores to scramble to find prey. lions were unaffected.
Lions reappeared in the fossil record of East Beringia about 22,000 years ago. At this time, the last wave of cave lions arrived from Asia. But they had bad luck.
At the end of the last ice age, temperatures rose and large animals across the continent began to die. This was aided by the presence of humans, who began to rapidly alter the environment. Michen says.
Paleontologist and former lecturer at the University of Liverpool in England, Andrew Cuffe, who was not involved in the Salis study, said it makes sense that lions invaded North America in multiple waves, with Beringia passing through. He notes that many animals, including dinosaurs, used this route to travel between continents.
Cuff adds that it’s great that the data can be put together like this to tell a coherent story that also matches the glacial, fossil and DNA records.
Lions weren’t the only cats that roamed North America in the Pleistocene. Cougars (also known as leopards, pumas, and mountain lions) and several now-extinct species, including various saber-toothed tigers, spread across the Americas long before the arrival of lions. North American cougars were victims of post-glacial megafauna extinction, but South American populations survived, Miesen says.
North America was incredibly dense with species diversity before the end of the Ice Age, says Miechen. She hopes that by knowing what has been lost, more people will come to understand the importance of biodiversity and the need to preserve it.
This article first appeared on hakai magazine Republished here with permission.
