Origin of the European Roe Deer (Capreolus capreolus)
Opinions of palaeontologists vary about the origin the roe deer, but fossil remains in the Ukraine of one of the oldest ancestors of the modern roe deer dates back 10 million years.
Moreover, some of the earliest evidence of the modern species of roe date back 3 million years and have been unearthed in Russia and Slovakia. Later fossils have found in Siberia (1 million years) and Germany (600 hundred thousand years).
The earliest ancestors came from the taxonomic category of Procapreolus. There were seven species of ancient deer Procapreolus, and of those seven species, Capreolus is believed to have descended from Procapreolus wenzensis, about 3 million years ago (from fossil evidence in western Russia).
Roe Deer in Great Britain
The roe deer we have in Britain are the European species of roe (Capreolus capreolus), but there are some inconsistences in the scientific literature as to how far back in time you can reliably trace back evidence of Capreolus capreolus living with these isles.
In 1984 A.M. Lister said that the European roe deer was present in Great Britain as far back as half a million years ago (ref. Evolutionary and ecological origins British deer, Proceedings of the Royal Society of Edinburgh, 82B, pp205-229). And there is certainly evidence of fossilised roe dating back 10 thousand years found at Star Carr, which is a Mesolithic archaeological site in North Yorkshire, and at another site near the old Berkshire town of Thatcham.
The evidence takes the form of fossilised bones found in ancient refuse sites located at early settlements. (Evidence suggests the people have lived in the area now known as Thatcham for over 12 thousand years, and it’s likely that early man hunted roe deer for food, hence the existence of fossilised bones in their refuse.)
Climatic oscillations created periods of glaciation in Britain and over time, the extent of forested areas has varied in unison with the occurrence of the ice ages i.e. deforestation during cold periods and reforestation during the intervening warm periods. Since roe deer are an animal that needs considerable woodland cover, it is possible that ever since Capreolus capreolus has been able to move in and out of Britain, their movements into and out the country have varied accordingly.
Fossil remains suggest that during periods of maximum ice cover, roe deer were primarily resident in the Mediterranean areas of Europe. Populations then moved northwards again as the ice sheet retreated. Roe deer then last moved into Britain about 10,000 years ago (just after the last ice ended), and have been here ever since.
Why Are There No Roe Deer Found in Ireland?
The reason why there are no roe deer in Ireland is due to the fact that the melting ice sheet created the Irish Sea about 12,000 years ago, separating it from mainland Europe and Great Britain before the deer had re-entered the region.
Rising sea levels formed English Channel about 8000 years ago, but by then, the deer had moved into Great Britain in numbers from the continental mainland, hence giving rise subsequent populations found in England, Scotland and Wales.