In 1939, archaeologists excavating a cave in
Germany made a pretty exciting find: fragments of an ancient figurine carved in mammoth ivory,
dating to around 30,000 to 40,000 years ago. The figurine - one of the oldest ever found -
is beautiful…and strange. Its body is that of a person, upright and bipedal, but it has
the head of an animal - a very big cat. It’s been interpreted as the earliest
artistic example of humans combining two real things into one imaginary thing
-- a fusion of forms, human and non-human, that may have had some complex,
symbolic meaning we’ll never know. And it isn’t the only artistic evidence left
behind by ancient people living in Eurasia that tells of a time when they shared their
environments with some kind of fearsome feline. The cave art of Chauvet in France, for
example, dating to around the same time, also shows these beasts prowling the landscape. And their fossils have been
found across the continent, from Spain and Portugal in the
west to Siberia in the east, even stretching into the Yukon, dating to
as recently as around 13,000 years ago. But what exactly were these big cats that ranged
throughout Eurasia during the last ice age? Figuring out their identity has been a scientific pursuit of ours for over a century
– but the artistic evidence makes it clear that our fascination with
them goes much, much further back. This mysterious big cat
was first described in 1810 from a skull found in a cave in southern Germany. And since then, many more of their
fossils have been found spanning the Late Pleistocene epoch, from at
least 129,000 to 13,000 years ago. The fossil evidence shows us
that they were Eurasia’s most widespread mega-carnivore of this period. In spite of this, scientists haven’t always
agreed on what kind of big cat they actually were. In 1866, a study argued they were just an odd
population of the modern lion, Panthera leo, that had migrated north and adapted to the cold. Over a hundred years later, a 1985
paper took it one step further, calling them their own subspecies. Things got weirder in 1996 when two researchers
suggested that they might not have been lions at all, but were actually
more closely related to tigers. And by 2006, some proposed that they
were a different species entirely: a distinct - and now extinct - species of lion
with much deeper evolutionary roots in Eurasia, called Panthera spelaea. Whatever they actually were,
based on the fact that many of their remains turned up in caves,
they became known as cave lions. …Which is probably just because caves are
really good at preserving stuff. They’re actually thought to have spent most of their
time in open grassland and wooded habitats. But isotopic analysis of the bones of a few
individuals also suggested that juvenile cave bears were part of their diet, so they may
have hunted in caves, at least some of the time. And while their skeletons did look more like those
of lions than tigers, there were some differences. Like, cave lion fossils were bigger,
although there was some variation. Fossils from Beringia - the area between the
Lena River in Siberia and the Mackenzie River in Canada - were smaller than those from Europe,
possibly due to different prey preferences. And studying the artwork made by the
ancient people who lived alongside them also gave us some clues about their identity. The depictions hint at some similarities with
modern lions, like the paintings of Chauvet showing them as social animals
that lived together in groups. But they consistently show some differences too. For example, the cave lions are never painted
or sculpted as having manes, even the ones that are clearly male… which we know because the
artists included the detail of visible genitalia. And, to add to all that evidence, in
recent years we’ve even found frozen cave lion cubs buried in Siberian permafrost! Four have been unearthed so
far, including one named Sparta, which is probably the best-preserved
ice age animal ever found. Despite being tens of thousands of years old, these cubs look like they died yesterday, giving
us a pretty incredible window into the past. Being able to actually see
a cave lion is something no one has done for something like 13,000 years. And it’s revealed some other differences between cave lions and modern lions – ones that
weren’t preserved in artwork or fossils. Like, for example, the cubs have a thick undercoat of curly fur - something
not seen in living lion cubs. This probably gave cave lions
better thermal insulation, which would have been pretty important
in their chilly northern habitat. In contrast, the fur of modern lions
is better suited to warmer climates, where protecting against
overheating is the bigger priority. So, while these three lines of evidence
all hinted at some physical differences between cave lions and living lions, they
couldn’t tell us how the two were related. Was one a subspecies of the other or
were they different species entirely? Or were they actually tiger-relatives? For that, we needed cave lion DNA. But getting good ancient DNA
is often easier said than done, because DNA begins to break down almost
immediately after death and degrades pretty fast. If remains are kept in just the right conditions, though - usually cold, dry, and away from
sunlight - their DNA can be preserved. But even in ideal conditions,
there's only so far back you can go. The oldest ancient DNA we’ve ever
been able to sequence comes from a mammoth that died about 1.6 million years ago. Luckily, cave lions meet many of the
requirements for ancient DNA preservation. Their remains have turned up both
in cold permafrost and in dark, dry caves, and they date to within
the time limits for ancient DNA. This has meant that, in recent years, researchers have actually been able to extract and
sequence the DNA of many cave lions. Finally, two centuries after
first describing their fossils, studying their DNA has helped us
solve the puzzle of their identity. It has confirmed that modern lions are the
closest living relative of the cave lions, but it also shows that the two were distinct species
that diverged from one another in the deep past. The most recent genetic analysis
from 2020 estimates that this split happened somewhere between
500,000 and 2.9 million years ago. And the DNA data also revealed a
split within cave lions themselves! Sometime between about 124,000 and 1.1 million
years ago, two populations diverged from one another, with one group mostly living
in Eurasia and the other in Beringia. Which helps explain why the fossils of cave
lions from those places were different sizes. So, it turns out that there were actually at least two subspecies of cave lions - one
in the east and one in the west. And the genetic evidence has also helped shed
some light on Panthera atrox, the American lion. They were a third kind of lion around
in the Late Pleistocene, along with cave lions and the ancestors of modern lions,
and they were the biggest of them all. And like the Eurasian cave lions, their
origins had been pretty contentious. But DNA analysis of both species revealed a
surprising evolutionary link. Cave lions and American lions seem to be sister lineages that
split from one another around 300,000 years ago. This may have happened when a population of
cave lions in Beringia migrated further into North America, eventually becoming isolated by
ice sheets and giving rise to the American lion. The Eurasian cave lion was a key player
in the diversification of lions during the Pleistocene - a period that saw the
radiation of many other large mammal groups. Despite rising to the top of the Eurasian food
chain, ranging over a vast territory, and even spawning another separate lion species, their
story came to a close around 13,000 years ago. A combination of climate change, changes in prey
abundance, and maybe even increased pressure from humans eventually drove them extinct, along
with many other Late Pleistocene megafauna. But they certainly left their mark on
us - in the ancient art they inspired and in the many questions raised by
that strange, lion-headed figure. Right ‘meow’ we’ve got to thank
this month’s /paw/some Eontologists! By becoming an Eonite at patreon.com/eons you
can get fun perks like submitting a joke for us to read, like this one from Philip
What sort of tea does a King drink? Tea Rex.
And as always thank you for joining me in the Adam Lowe studio. Subscribe
at youtube.com/eons for more fabulous fossils.
Very cool so much in history we do not know