Rhinos one of few speces to survive

I HAVE always been fascinated by the large animals that roamed the world during and just after the last Ice Age.

I’m also intrigued by the arguments over when and why they became extinct. These animals, mostly mammals but including some birds and reptiles, are called the Pleistocene megafauna by zoologists.

Probably the best known ones from northern Europe and Asia are the woolly mammoth and the woolly rhinoceros. Mammoths were not quite as large as people imagine – slightly shorter than an Asian elephant, which itself is smaller than an African bush elephant, but heavier because they had a stocky build to help them withstand the cold. For the same reason they had much smaller ears and a thick coat of fur up to a metre long.

But woolly rhinos were large creatures, considerably bigger than any modern rhinoceros. They do have one living relative – the diminutive and endangered Sumatran rhinoceros. They had two horns, but there was also a rhino-like creature called elasmotherium which only had a single horn. It may be the origin of the unicorn legend.

These creatures mingled with our own giant Irish elk, wild horses called tarpan, a breed of wild cattle called the aurochs and the European bison or wisent. They were preyed on by wolves and cave lions, which were about 10% larger than modern lions.

There was a drastic reduction in the numbers of these animals between 10,000 and 8,000 years ago and some of them became extinct, or only lingered on in isolated pockets. Most mammoths died out but some survived on arctic islands. There was certainly a dwarf race of woolly mammoth living on Wrangel Island 3,700 years ago and other populations may have survived elsewhere.

There are some intriguing historical accounts that suggest that small populations of elasmotherium were being hunted by humans in remote parts of north eastern Siberia 1000 years ago, or perhaps even more recently.

Cave lions seem to have hung on in the Balkans until about 2000 years ago. The last aurochs died of old age in a Polish forest in 1627. Tarpan died out in the wild between 1875 and 1890 and the last captive specimen died in a Russian zoo in 1909.

The wisent nearly went the same way. When the First World War broke out their main stronghold was a forest called Bialowieza on the border of Poland and Belorus. German troops occupied the forest and killed 600 of them for food before a conservationist officer intervened. Despite his intervention only nine were left by the end of the war. Another small population in the Caucasus was hunted to extinction in 1927.

But there were just under 50 specimens in zoos and from this small gene pool several thousand have been reintroduced into the wild.

But what happened between 10,000 and 8,000 years ago that caused the bulk of the megafauna in Europe, Asia and North America to become extinct? For a long time mainstream scientific opinion put it down to climate change, possibly assisted by epidemic diseases.

A new theory was developed that claimed that the extinctions were caused by a new and deadly set of predators arriving on the scene. Humans and Neanderthals were spreading rapidly out from Africa and southern Asia and colonising the northern hemisphere.

The real answer is that it was probably a combination of factors that caused the extinctions, but that our species is not beyond blame.

* dick.warner@examiner.ie


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