MEGAFAUNAL EXTINCTIONS | How the Mighty Fell:

The Four Phases in the Megafaunal Extinctions of Northern Eurasia

Last month we were introduced to the great raft of megafaunal species that disappeared in northern Eurasia, and though we saw that the extinctions in this region were less severe than in some other regions, it was also very clear that among the casualties were a great many mammals of impressive size and form. This month, then, we will strive to understand more about when, how, and why these mighty mammals fell, and it will become evident that the reasons for their disappearance are very complex. We will also see that the megafaunal extinctions in northern Eurasia, unlike those in other regions, have a direct relevance to the nature of modern Irish people, with one of their consequences being that they altered the very meaning of what it is to be human.

We must begin our investigation with an attempt to establish when the various megafaunal species in northern Eurasia disappeared. As it happens, four different phases have been identified in the sequence of megafaunal extinctions in this region, which we can now look at in turn.

Phase 1: 117,000–40,000 years ago

The first phase in the megafaunal extinctions of northern Eurasia occurred early in the last glacial, between 117,000 and 40,000 years ago, when the hippos, straight-tusked elephants, and narrow-nosed rhinos went extinct.

During the warmth of the last interglacial (c. 130,000–117,000 years ago), hippos ranged from Africa in the south to Britain in the north, and these fossil forms were even larger than their modern relatives in Africa. Although we have few fossils dating from this time in Ireland, it is at least conceivable that hippos were also present in ancient Irish waterways during this balmy interglacial. However, as the interglacial ended and the cold of the last glacial period set in, hippos were wiped out in mainland Europe, although some pygmy forms persisted on Mediterranean islands like Cyprus.

The straight-tusked elephant (Palaeoloxodon antiquus) was another gigantic mammal present in Britain and much of the rest of Europe during the last interglacial. Due to the aforementioned lack of fossils, though, it is impossible to know if this massive elephant lived in Ireland at this time. Although it may have been present in Ireland in the Early Pleistocene (2.6–1.8 million years ago), as it is known to have inhabited Britain at this time and these lands may still have been joined together, from this time on Ireland is thought to have been separated from Britain during interglacial periods by a wide expanse of sea which may have prevented even relatively proficient swimmers like elephants from making a crossing.

In any case, this elephant lived in the forests, and as the last glacial set in and the forests retreated south, it retreated south also, possibly surviving in Iberia until around 70,000–50,000 years ago, although recent radiocarbon-dated fossils from the Netherlands and the North Sea suggest that it may actually have persisted in northwest Europe for even longer, perhaps as late as 37,000 years ago.

The narrow-nosed rhino, Stephanorhinus hemitoechus, is another bulky giant known to have roamed widely during the last interglacial, but, like the others, the remorseless advance of the last glacial eventually caught up with it, and it was wiped from its last refuge in southern Europe by around 45,000 years ago.

Phase 2: Millennia preceding onset of the Last Glacial Maximum 26,000 years ago

The second phase in the megafaunal extinctions of northern Eurasia appears to have taken place in the millennia running up to the onset of the Last Glacial Maximum, which began around 26,000 years ago.

The spotted hyena, which, as we saw back in February, was present in Ireland and much of the rest of Eurasia in the late Ice Age, is said to have gone extinct in Europe and the rest of northern Eurasia around 31,000 years ago, although the most recent fossil from Castlepook Cave in Co. Cork dates from not much over 28,000 years ago, so it may have persisted a little longer than is generally believed. At the other end of Eurasia, Naumann’s elephant (Palaeoloxodon naumanni) is also thought to have disappeared around 28,000 years ago, while, back in western Europe, the cave bear (Ursus spelaeus) went extinct shortly after this. Other large forms, such as the cave lion (Panthera spelaea/Panthera leo spelaea) and the giant Irish deer, also disappeared from Europe during the Last Glacial Maximum but survived farther east.

That gigantic, elaborately-horned rhino, the 3.5-tonne 'Siberian unicorn', Elasmotherium sibiricum, is also thought to have gone extinct in northern Eurasia before the Last Glacial Maximum. Although once thought to have vanished from the Earth around 200,000 years ago, in 2018 new evidence was reported which proved that it was still alive in Eastern Europe and Central Asia at least as late as 39,000 years ago. As there are no fossils of this massive beast dating from after the LGM, though, it is thought to have perished before the descent of this bitterly cold period, possibly around 39,000–35,000 years ago.

Of course, one of the most interesting elements of the Pleistocene megafauna to disappear from Europe before the onset of the Last Glacial Maximum was a close relative of ours, the Neanderthal. But though the extinction date of this ancient human species has traditionally been stated as around 30,000 years ago, this has recently been revised upwards to around 40,000 years ago. Their extinction is still, though, regarded as belonging to the second phase of megafaunal extinctions which occurred before the Last Glacial Maximum in northern Eurasia.

Phase 3: 15,000–4,000 years ago

The third phase in the extinctions of the megafauna of northern Eurasia took place between around 15,000 and 4,000 years ago, with some of the most impressive species breathing their last. For instance, both the woolly rhino and the cave lion went extinct around 14,000 years ago, while some other hulking forms such as the steppe bison survived into the Holocene (c. 11,700 years ago–Present), its last remains coming from deposits in northeast Siberia dating to just under 9,000 years ago.

An even greater form to disappear in this third phase, of course, was the wondrous woolly mammoth, Mammuthus primigenius. During the late Ice Age, this behemoth’s range shrank and shrank – for instance, we know it never returned to Ireland after the Last Glacial Maximum – and it went extinct in almost every land it had once been perfectly adapted to. However, we also now know this Ice Age giant managed to cling on in a few places for thousands of years after the Ice Age ended.

As the Ice Age gave way to the Holocene and the seas rose, woolly mammoths became isolated on some islands off the coast in the northern regions of the world. Here, they lived their lives for many generations, persisting on St. Paul Island off the Alaskan coast south of the Bering Strait up until less than 6,000 years ago, around the same time that the first farmers were arriving in Ireland. Their very last holdout, though, was on Wrangel Island off the coast of northeast Siberia to the north of the Bering Strait, where the bones of their last members date to as recently as around 3,700 years ago. Not long before the ancient Irish were trumpeting with their impressive Bronze Age horns, then, thousands of kilometres away the mammoths were trumpeting their last.

Of course, another Ice Age king that we now know also survived into the Holocene is that species we are particularly interested in, the giant Irish deer, Megaloceros giganteus. Like the woolly mammoth, this fantastic beast disappeared from almost every land it had once inhabited as the Ice Age ended and the Holocene began, and is thought to have vanished from western Europe between around 12,800 and 12,400 years ago, as the last pulse of cold, the Younger Dryas, kicked in just before the Ice Age came to an end. As we have previously seen, though, it too managed to cling on in a refuge for thousands of years after the Ice Age ended, the last members of this great species not succumbing to extinction until around 7,700 years ago in western Siberia on the eastern side of the Urals.

Phase 4: 4,000 years ago–Present

Finally, the fourth phase of the megafaunal extinctions in northern Eurasia took place from around 4,000 years ago up to the present. Around 3,000 years ago, two quite different species disappeared, with the European ass, Equus hydruntinus – widespread across western Eurasia in the late Ice Age – progressively disappearing across its former range during the Holocene, with its last members hailing from the Caucasus, while the last musk oxen (Ovibos moschatus) in northern Eurasia made their final stand in the northern Siberian tundra.

Other species that have disappeared from northern Eurasia during the Holocene but survived elsewhere include the lion (Panthera leo), which is thought to have held out in southeastern Europe up until around 2,000 years ago. Its relative, the leopard (Panthera pardus) has fared much better, still maintaining a presence in northern Eurasia in various locations from Turkey to eastern Russia, although having gone extinct in south and central Europe during the Holocene and being vulnerable in the areas it still inhabits.

Other megafaunal species have disappeared from northern Eurasia only hundreds, not thousands, of years ago. For instance, the aurochs (Bos primigenius), the wild bovine species that is ancestral to Ireland’s modern domesticated cattle, only went extinct as recently as 1627 when the last known individual expired in the Jaktorów Forest in Poland.

Possible causes

So, after looking at the megafaunal extinctions of northern Eurasia it should be very clear that they extend across an enormous span of time and involve a great diversity of forms. Thus, searching for any one cause for all these extinctions would undoubtedly be an exercise in futility. To pick out just a few examples, we can see that changes in climate and vegetation may have been the primary drivers for some extinctions.

For instance, it may have simply been the deepening cold which killed off the spotted hyena, while the cave bear may have been laid low by both the decreasing temperatures and its more herbivorous nature, as the plants it relied on diminished in quality and abundance. Similarly, the extinctions of hairy goliaths like the woolly mammoth and woolly rhino appear to have been primarily driven by climatic and vegetational changes, as the vast grasslands of the Mammoth Steppe which stretched from the Yukon to Britain were colonised by trees and shrubs as the climate warmed around 14,700 years ago, depriving them of their favourite foods.

The earlier extinction of the gigantic rhino Elasmotherium sibiricum too is thought to relate to a change in the plants it fed on as the vast grasslands it relied on fragmented due to the deepening cold, as this rhino was, like living forms, a picky eater. This, combined with its restricted geographical range, its slow rate of reproduction, and low population size may have ushered it to extinction while its relatives like the woolly rhino managed to cling on in the region for another 20,000 years.

And yet, as with the other regions, a human hand in some of the megafaunal extinctions in northern Eurasia cannot be discounted. In Europe alone, for instance, modern humans had arrived by 45,000 years ago, so were present when the vast majority of the megafaunal extinctions took place. And while a rapid overkill scenario definitely doesn’t fit the picture, with many megafaunal species on that continent suffering extinction tens of thousands of years after modern humans first arrived, their presence may have been an added burden on species which were already struggling to survive.

Modern humans may conceivably have contributed to the demise of some species by inhibiting the expansion of their ranges or through hunting. Certainly, to take one specific example, the European ass is thought to have been driven to extinction by climatic and vegetational changes allied with human pressures, with the decrease in the open habitats they were adapted to combining with human hunting to seal their fate.

As for that megafaunal species modern humans are most closely related to, Homo neanderthalensis, better known simply as the Neanderthal, exactly what precipitated their demise is unknown and many different causes have been put forward. Certainly, competition with modern humans may have been a factor, but the picture of Neanderthal extinction is very complex, as is the picture of their interactions with modern humans.

For example, as we have previously seen, interbreeding is now known to have taken place between these two human groups, and Neanderthals are among the ancestors of the Irish and all other modern humans outside Africa (and even a few within it). The extinction of the Denisovans is shrouded in even greater mystery, and though we know that modern humans also interbred with them, we do not yet know exactly when they went extinct or if modern humans had a hand in their demise.

In the end, the evidence regarding human involvement in the megafaunal extinctions in northern Eurasia is, like that from the other regions, inconclusive, and the best we can say is that our species, Homo sapiens, may have played a part. What our investigation does reveal with crashing clarity, though, is just what we have lost.

Northern Eurasia may not have been the region worst hit by the megafaunal extinctions, but many of the species lost were truly fascinating forms. It is also clear that the loss of large mammals in this region was profound in a way that cannot be said of that in worse-affected regions such as the Americas and Australia. For the megafaunal extinctions in northern Eurasia contributed to the position of preeminence in which the Irish and all other humans find themselves in the modern world, with all of our human relatives now extinct, our closest kin today being no fellow, upright, bipedal member of the genus Homo, but that tree-dwelling, branch-swinging great ape, the chimpanzee. We are the last humans left standing. We are special. We are unique. We are alone.