MEGAFAUNAL EXTINCTIONS | The Verdict:

Did the First Irish Drive the Extinction of the Giant Irish Deer?

Finally, after an in-depth investigation into the megafaunal extinctions which over the last number of months has taken us across the world, transporting us to many locations in both time and space, here we are, ready to deliver a verdict on the question that launched our exploration back in July 2016: did the first Irish drive the extinction of the giant Irish deer?

Over this half-year stretch we have sifted through the evidence for the megafaunal extinctions in each major region of the world, and in some respects this has been quite a harrowing journey. But just as this investigation has in some ways mirrored the shift in the seasons over the time it was conducted, with a steady descent into deeper darkness as we learned of the light of countless fascinating species being extinguished, so too has it provided illumination, casting light on the reasons why these great beasts suffered extinction and the possible role humans played in their demise. Thus, with all this information having sharpened our senses, we can now turn our gaze back to the Ireland of the late Ice Age and see it with keener eyes, a much clearer picture materialising of the extinction of the giant Irish deer in this land and the possible part played by the first modern humans on the island.

The most logical place to begin is with the extinction of the giant Irish deer itself – that is, exactly when did it disappear from Ireland? Last month, we saw that it is generally thought that the giant Irish deer went extinct in western Europe between around 12,800 and 12,400 years ago, but to pinpoint when it vanished from Ireland we must turn to fossils that have been found on the island itself.

Well, there is, in fact, one skull of a giant Irish deer that was found in the early 1890s in Belfast which was said to come from deposits that date to the early Holocene (c. 11,700 years ago–Present). However, the man who published this find acknowledged that he was not actually present when the discovery of the skull was made, and so it may very well not have come from those deposits at all, and so not be post-glacial in age. In any case, this is the only evidence to support a claim of survival of the giant Irish deer into the Holocene in Ireland and most regard it as extremely dubious.

Disregarding that specimen, all of the others of most recent age date to over 12,000 years ago. The most recent is a fossil from Ballybetagh bog in Co. Dublin that has yielded a radiocarbon date of 10,610±495 BP (years before present), which equates to a calendar date of just under 12,400 years ago. However, this date is not without its own problems either, as the standard deviation in the radiocarbon date (the ±495 part) is very large – that is, 12,400 years ago is the midpoint within a date range spanning over 2,000 years – and so this cannot be regarded as a very precise date.

And the problems with this fossil do not stop there, as became very clear in early September 2018 when a giant Irish deer skull with antlers was hauled from the waters of Lough Neagh in the north of Ireland by local fishermen. In the reports on this spectacular find, it was widely stated that the giant Irish deer had gone extinct in Ireland around 10,500 years ago, and experts who should know better also quoted this date. And this is doubly problematic.

If it was indeed the Ballybetagh bog fossil which was used to determine that date, these 'experts' not only used a specimen which is very imprecisely dated, but they also quoted the UNCALIBRATED radiocarbon date for the fossil as if it was a calendar date. It was, in fact, once believed that radiocarbon dates equated exactly with calendar dates, but it has been known for quite a while now that they don't, as the amount of carbon in the atmosphere has fluctuated over time so radiocarbon dates need to be calibrated to take this carbon variation into account and the date is then expressed in calendar years before 1950. In the case of the Ballybetagh bog specimen, its calibrated date is 12,326 years cal BP (calendar years before 1950), which, even if you were going to ignore the issue with the large standard deviation, would place the extinction of the giant Irish deer almost two thousand years earlier than was reported.

In any case, disregarding the Ballybetagh Bog date also, we are left with three fossils, one of which is of unknown provenance while the other two come from opposite ends of the island – from Kilgreany Cave in Co. Waterford in the southeast, and Milewater Dock in Belfast in the northeast. These fossils all fall within a date range of just over 12,900 years ago to 12,800 years ago. Thus, if these fossils do truly reflect some of the last occurrences of giant Irish deer in Ireland, it would appear that it may have been one of the earliest locations in which this Ice Age giant suffered extinction in western Europe.

And this extinction date for Ireland is very interesting in terms of our investigation of the possible role played by the first Irish in the disappearance of this magnificent beast. This is because, as we saw in the post for June 2016 on the first Irish, new evidence has now shown that this was right around the time modern humans first appeared on the island, with knife-marks on a brown bear kneecap attesting to a human presence in Ireland between around 12,800 and 12,600 years ago.

On the face of it, this would appear to be damning evidence of a possible overkill scenario in Ireland, with the giant Irish deer driven to extinction shortly after the arrival of the first Homo sapiens on the island. Certainly, the humans that inhabited other lands in northwestern Europe at this time are known to have been, like their contemporaries in Clovis-era North America, skilled hunters capable of taking down very large prey, and there is no reason to think the first Irish were any different. Indeed, as we saw in the post on the first Irish, it is possible that the bear kneecap proving a human presence in late Ice Age Ireland came from an animal that was set upon by hunters while it was hibernating in a cave, this ancient hibernaculum perhaps swiftly converted to a gruesome deathbed by the deadly descent of a storm of spears.

And yet, this evidence is circumstantial at best, so before we let the gavel fall and in thundering tones proclaim a verdict of “Guilty!”, we should interrogate all the other evidence at our disposal to ensure a more balanced judgment.

For instance, one very important question to ask is: does the newly rediscovered evidence proving the presence of modern humans in Ireland around 12,800–12,600 years ago really reflect the first arrival of humans on the island or is it simply the earliest evidence of a human presence to have survived? In other words, could modern humans have arrived in Ireland much earlier than this evidence implies?

Well, again, as we saw in the post on the first Irish, northwestern Europe was recolonised by modern humans after the Last Glacial Maximum (which lasted from around 26,000–19,000 years ago), far earlier than the date we have for the first presence of modern humans in Ireland. Indeed, our nearest neighbour, Britain, is known to have been inhabited from around 15,000 years ago onwards, and evidence of human habitation has been found in sites bordering the Irish Sea, in western Scotland and Wales.

It is at least conceivable, then, that humans inhabiting Britain may have made landfall in Ireland at some point between the time they first arrived in that land, around 15,000 years ago, and the date we currently have for the first Irish of 12,800–12,600 years ago. This is a time span of over 2,000 years, and it is far from unthinkable that some band of humans may have sailed across the ancient Irish Sea to exploit the resources of this terra incognita. And if they did, this would weaken any case for a swift overkill scenario for the extinction of the giant Irish deer in Ireland.

But even if we accept the 12,800–12,600 years ago date to be true evidence of the first modern humans in Ireland, other questions remain. For instance, when we looked at the megafaunal extinctions in Australia, one striking point was that though we now know that modern humans arrived on that continent by 65,000 years ago, or possibly even earlier, genetic evidence from living Aboriginal people has shown that their populations remained low for the vast majority of this time, only becoming larger around 10,000 years ago. This is a piece of evidence which argues against them having the capacity to drive many megafaunal species to extinction.

So, this leads us to the question: were the first Irish present in sufficient numbers to drive the extinction of the giant Irish deer?

Well, this is a hard question to answer. One thing we can say is that the first Irish appear to have been only present in low numbers, as indicated by the study that announced the discovery of the new evidence for the first Irish of the late Ice Age. In this, the authors note that around 12,800–12,600 years ago, Britain was only sparsely populated, that most evidence of human habitation comes from southeast England, and that this evidence may come from only very small groups of hunters that moved into Britain – which was still connected to the Continent – for only months at a time to capture reindeer and horse.

It would appear, then, that there was no vast reservoir of humans in Britain from which a large-scale colonisation of Ireland could take place at this time, and the authors conclude that the arrival of the first Irish ‘may reflect a brief small-scale human incursion.’

So, the first Irish certainly seem to have been present in low numbers, but this still leaves us with the question as to whether such low numbers could still have been sufficient to drive the extinction of the giant Irish deer.

The conclusion to the post on the megafaunal extinctions in the Americas included the speculation that ‘Maybe ancient Americans whose ancestors had lived beside megafaunal species for thousands of years were forced to prey on them to an even greater degree with the onset of the climatic downturn of the Younger Dryas around 12,900 years ago, and for these large, slowly-reproducing mammals this was simply the straw that broke the camel’s (or the mastodon's) back.’ Could the arrival of the first modern humans in Ireland have had the same effect on the giant Irish deer? Did their presence, even in low numbers, constitute an added burden on a species of giant already on the precipice of extinction on the island, tipping it over the edge to oblivion?

Although this is possible, on balance it would seem that the first Irish would not have been present in great enough numbers to have had such a crippling effect on the survival of a species that even in its last days appears to have inhabited widely separated parts of Ireland.

So, finally, what is our conclusion – did the first Irish drive the extinction of the giant Irish deer? In the end, our verdict must be 'not guilty' due to insufficient evidence. And yet, as we have seen with the megafaunal extinctions in many other regions of the world, an absence of conclusive evidence is far from an endorsement of resounding innocence. This acquittal leaves us with our suspicions regarding a possible role played by the first Irish in the disappearance of the last of the island’s great Ice Age kings, and though we cannot clearly trace the footprint of unsustainable human activity being pressed into the earth at this time, we can almost see the outline of a toe or two. But whatever the truth of all this, our investigation leaves us with far more than suspicions, having brought us closer to understanding the nature of the first modern humans known to have inhabited Ireland. Whatever they did, however they lived, they hold a very special place in the story of the evolution of Ireland – they were the first Irish.

P.S.: And maybe, just maybe, the extinction of the giant Irish deer in Ireland had nothing at all to do with the arrival of humans...