by Tim Flannery
If a changing climate was to blame for the extinction of the straight-tusked elephants, why should they have survived on islands long after those on the adjacent mainland vanished? Surely climatic shifts would affect islands and the adjacent mainland equally? The fact that the pygmy elephants survived on Cyprus until around the time that humans discovered their island is, I think, telling. The cold phases of the ice age were bad news for straight-tusked elephants, but there was another, more decisive influence at work—humans.
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* Also known as the African forest elephant.
CHAPTER 29
Other Temperate Giants
After elephants, the largest creatures humans encountered in Europe were rhinos. Merck’s rhino and the narrow-nosed rhino were close relatives, having diverged from a common ancestor a million or so years ago. The larger Merck’s rhino (which could weigh up to three tonnes) was a specialised browser, much like Africa’s black rhino, while the narrow-nosed rhino fed on grass, as does Africa’s white rhino. Although ecologically similar, neither species was closely related to the African rhinos living today.* Instead, rather surprisingly, Europe’s extinct rhinos were related to the Sumatran rhinoceros, which is critically endangered. The range of Europe’s rhinos extended far to the east: Merck’s rhino as far as Afghanistan, and the narrow-nosed rhino as far as eastern China.1
Despite the abundance of their fossilised remains, both species remain under-researched. A study of DNA could reveal much about their evolutionary relationships, and a careful dating program may tell us more about their extinction. They seem to have survived in Spain (Merck’s rhino) and Italy (narrow-nosed rhino) until about 50,000 years ago. But some 37,000-year-old depictions in Chauvet Cave, France, may also represent one of these species. The Chauvet depictions show beasts with dark bands around their girths, raising the intriguing possibility that they were patterned like Holstein cattle.
Hippo remains dating to around 100,000 years ago have been found in sediments in the lower reaches of the Thames and in the Rhine and Danube rivers. Hippos do not like severe frosts, and they retracted southwards as the climate cooled, before disappearing altogether from Europe long before humans arrived. The final member of temperate Europe’s big five was the water buffalo. Its fossilised remains abound in the river valleys of western and central Europe, particularly in the Netherlands and Germany. There appear to have been minor differences in horn shape between the European fossils and the living Asian water buffalo, prompting some to place the European fossils in their own species. Whatever the case, the extinct European population was very similar to the living Asian river buffalo. Its genetics and the date of its extinction have not been adequately researched, though the species may have survived in eastern Austria until about 10,000 years ago.2
Water buffalos are such useful animals that they were reintroduced to Europe. The Lombard king Agilulf may have been the first, bringing them to the Milan area in 600 CE. Armenia also received them early, and introductions have continued to the present, with domestic populations thriving today across Europe, from Romania to the United Kingdom. But perhaps the best place to see them is on the plains around Salerno in southern Italy, where their milk is used to produce the delicious mozzarella that the region is famous for.
Three of temperate Europe’s ‘big five’ are not extinct or have surviving close relatives: the straight-tusked elephant, the hippo and the water buffalo. It’s just that none has survived continuously in Europe, though the water buffalo was reintroduced early on and exists in domestic form. But other mega-herbivores flourished in temperate Europe before the arrival of Homo sapiens. In descending order of size they were: the aurochs, giant deer, cave bear, red deer, wild boar, fallow deer and roe deer. Of these, only the cave bear and giant deer are extinct, while all the rest survive in Europe in one sense or another.
Cave bears and European brown bears are close relatives, but brown bears occur in Europe, Asia and North America (where they are known as grizzlies) while cave bears were restricted to Europe. Both are descended from the ancestral Etruscan bear that existed a little over a million years ago. Brown bears and cave bears coexisted but seem to have divided the ecological niche by size and diet. European brown bears are today largely herbivorous, but bone analysis shows that in the past they ate lots of meat. Cave bears, in contrast, were purely herbivorous.3
Cave bears probably looked like oversized brown bears with dished foreheads. At a tonne in weight, they were twice the size of the largest European brown bears, and had skulls up to three-quarters of a metre long. The cave bear population started to decline about 50,000 years ago, contracting westwards until the last known populations remained in the Alps and adjacent areas, where they became extinct about 28,000 years ago.4* Both Neanderthals and human–Neanderthal hybrids hunted them: a 29,000-year-old vertebra found in Hohle Fels cave in the Swabian Jura retains the flint spear head that killed the animal, and cave bear bones (mostly juvenile) from the site have the marks of butchering and skinning. The evidence from Hohle Fels indicates that cave bears were important prey for the hybrid human–Neanderthals living there: for at least 5000 years they consumed their flesh, used their skin for rugs or clothing, their teeth for ornaments, and burned their bones for warmth.5
Countless fossils of the giant deer have been unearthed from Ireland’s peat bogs, and it seems that in the nineteenth century no Irish baronial manor was complete without the skull of an ‘Irish elk’ in the entrance hall. Its fossils occur across a vast swathe of Eurasia, from Ireland all the way to China. At more than 600 kilograms in weight the giant deer was the size of a moose. Its enormous antlers could weigh 40 kilograms and measure more than 3.5 metres tip to tip. Cave paintings indicate that it was pale in colour with a dark stripe over its shoulders. Its nearest living relative is the much smaller fallow deer, whose antlers are similar in shape.
Traditional explanations for the extinction of the giant deer focus on its antlers as being somehow maladapted to altered vegetation or climatic conditions, or on a decrease in accessible nutrition. But the evidence we have does not fit either theory. The last records are from northern Siberia, where it survived until about 7700 years ago, at which time the climate was broadly similar to today’s. Moreover, the most recent fossils show no evidence of malnutrition. Two skeletons found on the Isle of Man have been dated to about 9000 years ago.6 By this time, the Isle of Man had been cut off from the rest of Britain by rising seas for 3000 years. Both skeletons are from much smaller individuals than those that lived in the region just a few thousand years earlier. Their small size might be the result of island living, or perhaps a warming climate. Perhaps these ‘dwarves’ survived on the Isle of Man because their home had not yet been invaded by people?
Ice-age Europe’s rich and varied large carnivore fauna comprised brown bears, lions, spotted hyenas, leopards and wolves. Of these, only the brown bear and wolf survive in Europe today. The cave lion, an enormous predator about 10 per cent heavier than today’s lions, is only modestly distinct from the surviving lion species, having diverged about 700,000 years ago. Its appearance is well known from cave art, ivory carvings and clay figurines: it lacked a mane, was the same colour or a little lighter than the modern lion and had the same ears and tufted tails. But it had a dense underfur, and some may have been faintly striped.7* It had one of the widest distributions of any mammal, being found from Europe to Alaska, and ranging far into the freezing north. A pair of week-old cubs, at least 10,000 years old, was recently discovered, preserved in permafrost, in Siberia.
The diet of cave lions seems to have varied regionally. Some specialised, preying on reindeer, while others preferred young cave bears.8 After the arrival of humans in Europe, cave lions began to decrease in size. The most recent individual known, from northern Spain, was no larger than a living African lion. The discovery of a ‘living floor’ in the lower gallery of La Garma Cave, near Cantabria in Spain, which had remained undisturbed for 14,000 yea
rs, provides a remarkable insight into interactions between humans and the last of the cave lions.** Inside the cave, whose walls are decorated with art, were the ruins of three stone huts, located about 130 metres from the original entrance and dating to between 14,300 and 14,000 years ago. They appear to be the result of a single, relatively brief occupation that was terminated when a rockfall sealed the chamber. The bones of horses, aurochs, red deer, reindeer, brown bear, fox and spotted hyena are clearly the leftovers from meals. But around one of the huts lay nine claw bones of a cave lion. They were cut in a way that indicated that the creature had been skinned. Researchers believe that the claws, which are from the front paws, formed part of a lion-skin rug in one of the huts.9 Deposits of bones show that the hunting of carnivores by people had increased by the time La Garma Cave was occupied. Were carnivores being targeted because large game was scarce? Or were developments in hunting technology making it easier to kill lions and hyenas? Whatever the case, the La Garma claws are the last evidence of the cave lion in Europe.
After the cave lion, the next largest predator was the cave hyena. Attaining more than 100 kilograms in weight and at least 10 per cent larger than the spotted hyenas of Africa today, it was a formidable predator capable of killing a woolly rhinoceros. Despite its large size, genetic studies show that it belonged to the same species as today’s African spotted hyena.10 The species first arrived in Europe about 300,000 years ago, about the time of the extinction of the giant hyena, Pachycrocuta, which was twice its size. The cave hyena was widespread and abundant in Europe and north Asia, ranging from Spain to Siberia. Although present in virtually all habitats, it preferred to den in caves, so its distribution, especially in cold, northern areas, may have been limited to limestone and other rocky regions where caves form. Neanderthals and hyenas probably competed for caves, and hyenas seem to have occasionally pilfered Neanderthal kills, while Neanderthals occasionally killed and ate hyenas.
A study of climatic variability and hyena distribution in Europe indicates that the species’ extinction cannot be blamed on a shifting climate. In fact, the changing climate of Africa (where it survived) seems to have been even more challenging to the hyenas.11 While it is tempting to cite the arrival of humans as the cause, evidence is sadly lacking. All we know for sure is that 20,000 years ago, cave hyenas began to disappear from Europe.
Leopards, living males of which weigh between 60 and 90 kilograms, and females between 35 and 40 kilograms, were the next largest of Europe’s vanished predators. They once occurred as far north as England and might have survived until 10,000 years ago in western Europe.12 Today, Europe’s last leopards maintain a claw-hold in Turkey and Armenia, where they are critically endangered, with perhaps only a few dozen surviving. But leopards do not give up easily. In the 1870s, one swam 1.5 kilometres from Turkey to the Greek island of Samos. The creature was trapped in a cave by a local farmer and eventually killed, but not before it had inflicted fatal wounds on its persecutor.
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* Africa’s rhinos diverged from other rhinos around 24 million years ago.
* So far, an extensive dating program for late-surviving cave bears has only been conducted in the Alps. It’s possible that a few lingered on elsewhere in western Europe.
* The discovery of fur preserved in the Siberian permafrost has revealed details of colour and underfur.
** A living floor is, in archaeological terms, the floor of a cave upon which people lived and which retains evidence of their activities.
CHAPTER 30
Ice Beasts
When we hear the words ‘ice age’, we think of those frigid, treeless regions that at times expanded to become the largest habitat on Earth. The frozen north also had its big five, which included those iconic species, the woolly mammoth and the woolly rhinoceros. Both species were named in 1799 by Johann Friedrich Blumenbach, who is perhaps most famous for his naming of the races of humans. He believed that everyone was descended from Adam and Eve, and that the differences between the races resulted from environmental factors active since people had dispersed from the Garden of Eden, which was thought to have been in the Caucasus. Blumenbach believed that, given the right conditions, people would revert to their original Caucasian form. He possessed the skull of a Georgian woman which he thought was close in form to Eve’s. He probably thought of his fossil mammoth and rhino as close to the God-created individuals that inhabited Eden, for he named the woolly mammoth ‘primigenius’ (meaning ‘first’) and the rhino antiquitatis (‘of the good old days’). Essentially, Blumenbach’s classification relied on archetypes—the ideal of species as they were at the Creation.
The ice age was nearly two million years old by the time the woolly mammoth evolved. The Anglian glaciation, from 478,000 to 424,000 years ago, was particularly cold, and it marks a time of momentous change. One such change, which resonates even today, was a topographic alteration that has recently been termed the ‘geological Brexit’. Prior to the Anglian glaciation, a high chalk ridge had run from what is now the cliffs of Dover all the way to Calais. During warm phases, when the seas rose, this ridge provided the only dry land corridor linking Europe to peninsular Britain, and it would have acted as an ice-age highway for all land creatures migrating east or west.
By about 450,000 years ago melting glaciers had created a gigantic lake to the north of the chalk ridge, which filled until water began to pour over in a series of cascades so immense that they created ‘plunge pools’ up to 140 metres deep at their bases.1 A second breaching, about 160,000 years ago, completed the destruction of the ancient land bridge. During warm times, Britain became an island. The only land route was during cold phases, when sea levels fell, favouring colonisation by cold-adapted land creatures.
The Anglian glaciation acted as a spur for the development of a unique mammal assemblage known as the mammoth steppe fauna. This fauna, which would come to dominate Europe during cold phases, first occurred about 460,000 years ago.2 Its ‘core fauna’ consisted of the woolly mammoth, woolly rhino, saiga, muskox and the arctic fox.* All except the woolly rhino evolved in the northern Arctic, and all had been evolving for several million years before their modern forms appeared.
The woolly mammoth is the defining species of ice-age Europe in the sense that it is credited with helping create and maintain the largest habitat ever to exist on land—the mammoth steppe. Alaskan palaeontologist R. Dale Guthrie coined the term ‘mammoth steppe’. His interest in the vanished habitat was piqued by the observation that some of the regions the mammoth once roamed are today poor habitats, consisting of a thin layer of boggy vegetation lying over permafrost in which the nutrients are locked. These regions are barely capable of supporting bison, much less mammoths. He theorised that the very different habitat that existed during the ice age—was one created by the actions of the mammoths themselves. He thinks that mammoths, whose tusks acted as huge snowploughs (and are often found to be worn flat on the underside from such use), uncovered grass on which many beasts fed, so that by spring the vegetation had been cut back to bare earth, allowing the sun to warm the soil. This promoted swift new growth and prevented the build-up of boggy vegetation that could freeze into permafrost, locking away nutrients. In effect, intense grazing created a hugely productive habitat.
While supremely important in terms of ice-age ecology, the woolly mammoth itself is somewhat inflated in the public imagination. Some mammoths, including America’s Columbian mammoth, were indeed among the largest elephants ever, but woolly mammoths were on average no larger than Asian elephants. Asian elephants and woolly mammoths are close relatives, their ancestors having diverged in Africa only four to six million years ago.3 It was not until about 800,000 years ago that the classic woolly mammoth first appeared in Siberia. By half a million years ago it had reached western Europe.4
Quite apart from their luxurious covering of long hair and fur, woolly mammoths looked very different from today’s elephants, having a high-domed head, a pronou
nced shoulder hump of fat, and a back that sloped steeply to the rear. Their ears were tiny, their tusks were so curved that some crossed, their tails were short, and they were equipped with a ‘clapper valve’ that could cover their anus to protect it from cold.
Cave art has so exquisitely captured these majestic creatures that, seeing the images, we immediately comprehend the great, shaggy, hump-shouldered beasts, looming out of the cave wall and travelling in single file into the blizzard. Carcasses preserved in permafrost enable us to touch their long fur, study their parasites and prise lumps of food from between their teeth. It is even said that Siberian explorers feasted on mammoth flesh preserved in the permafrost.* More recently, advances in forensic DNA techniques have allowed us to recover the mammoth’s entire genome.
Following its arrival in the fossil record, the woolly mammoth appears across the breadth of Europe whenever the ice advances, except in the temperate refuges of the south. Yet, by 20,000 years ago it was in trouble. Detailed studies of mitochondrial DNA show that, beginning about 66,000 years ago, North American mammoths colonised Eurasia and gradually replaced existing types of mammoth until the Eurasian mammoths became extinct about 34,000 years ago. Strangely, the North American migrants don’t show up in western Europe until 32,000 years ago, leaving a ‘mammoth gap’ of 2000 years. Between 21,000 and 19,000 years ago, woolly mammoths are again absent from central continental Europe, and by 20,000 years ago they had gone from Iberia. They return briefly to Germany and France about 15,000 years ago, recolonising as far west as Britain, but within a millennium they vanish again. An adult male mammoth and four juveniles, trapped about 14,500 years ago in a boggy ‘kettle hole’ left by a retreating glacier in Shropshire, are the most recent record in the UK. With the demise of the last German mammoths about 14,000 years ago, the beast is gone permanently from Western Europe.5