Natural History

Red deer are currently the largest wild animals on the British Isles. It has been clear for a long time that the red deer of Great Britain are native, but when they colonized Ireland has always been a bit of a question.

Of course, not all deer in the British Isles are native.

Fallow deer were introduced to England by the Romans, but they may not have spread across the British Isles until the Romans arrived.

Reeves’s muntjac were introduced very recently.  Although traditionally believed to have been introduced at Wobun Abbey in Bedfordshire in the 1890’s, it is more likely that growing English muntjac population comes from other introductions. However, Chinese water deer were introduced at Wobun Abbey at the same time that the Reeves’s muntjac were supposedly introduced. The Duke of Bedford, who owned Wobun Abbey, also introduced a herd of Pere David’s deer from China. These deer did establish themselves there, and all Pere David’s deer still in existence descend from that naturalized herd. (They are extinct in the wild.)

Sika deer have been on both Great Britain and Ireland since the early 1900’s, and they readily hybridize with red deer. Sikas are close relatives the wapiti– the North American “elk”– and like the introduced wapiti of New Zealand, they do interbreed with red deer.

The only native deer in the British Isles are European roe deer and red deer. Roe deer are not currently found in Ireland, but they were introduced on an estate in County Sligo in the 1870’s. However, these roe deer died out after 50 years.

So it appeared that Ireland’s only native deer was the red deer.

However, a recent DNA study found that red deer also aren’t native to Ireland.

During the Pleistocene, Ireland was home to Meglaceros deer. In English, we often refer to these unusual animals as “Irish elk,”‘ and it was once famously suggested that Irish wolfhound were once used to hunt them. Too bad that they were extinct long before there were any dogs like Irish wolfhounds running about!

But this recent study is quite amazing.

A research team from Ireland, Austria, the UK, and the United States compared the DNA of ancient red deer bone specimens with modern red deer.

They found that red deer were introduced to the island about 5,000 years ago. The deer of County Kerry are particularly closely related to these ancient red deer and are thus a unique population.

5,000 years ago is about the same time the Neolithic Revolution hit Ireland:

The Irish Neolithic Period (c.4000 – 2500 BC) was when agricultural communities became established in Ireland. This involved the introduction of domesticated plants and animals to the island. The red deer appear to have been introduced as part of this change.

The study findings concur with archaeological evidence, which also suggests a special relationship between humans and red deer during prehistoric times. Antler fragments and tools are frequently found in Neolithic, Bronze Age and Iron Age excavations.

Red deer were very important to ancient Europeans.

Michael Jarman famously argued that ancient Europeans maintained what could be called “red deer economies.”  Jarman contended that Europeans managed red deer in order to propagate the species. These ancient Europeans culled mostly the young males and left the hinds and mature stags to produce the next generation. In this way, deer herds were kept as a resource, and the deer benefited from having a managed population that wasn’t as prone to boom and bust as they would have normally have been.

Of course, Jarman’s thesis has been attacked for being somewhat overly speculative. Hinds don’t leave behind antlers, and Jarman based most of his research on sites where there were lots of red deer antlers left behind.

And Benedetto Sala contends that Jarman’s thesis that the high mortality rate with young adult red deer is actually more the result of deer behavior rules than human hunting. When red deer hit the age of four or five, they are driven from their mother’s herd.

This leaves them open to human predators, which might go a long way to explaining why the antlers of so many young adult stags have been found at the sites Jarman examined.

But whether we accept Jarman’s hypothesis or not, red deer were very important to Mesolithic Europeans.

By the Neolithic, animal domestication was well underway. In places that were relatively late in receiving agriculture, domestic animals would have arrived already domesticated.

Red deer likely weren’t domesticated. They really aren’t now, even though they are managed in parks and bred at commercial deer farms.

However, it is likely that the Irish brought red deer over from Great Britain in order to have ready access to a game species.

After all, following the extinction of the Irish elk, there were no large game species on Ireland– except for wild boar.

Wild boar, it turns out, went extinct on Ireland roughly 5,000 years ago. It is thought that the deforestation that came with the arrival of agriculture made it impossible for the boars to survive.

Perhaps, the introduction of red deer in Ireland had more to do with the necessity of substituting one large game species for another one.

This study also shows that Irish wolves likely lived almost exclusively on wild boar for thousands of years, but they likely took to hunting red deer and domestic stock once that species became extinct.

The relatively late introduction of red deer to Ireland is a bit of a surprise.

But it shows that humans have been introducing species for thousands of years.

Introducing species is something we have done ever since we’ve mastered the seas. It’s just now that our ability to transport species from vast distances is also allowing us to release scores of invasive species throughout the world.

It’s not new.

It’s just now we’ve done it so much that it’s really having an impact across the globe.

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A special thanks to reader Ogre Magi for passing this one along!