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.