Nature of the beasts

As snapping and snorting sounds reverberate through the dense pine forest, the tops of nearby saplings quiver. Deep in Romania's Tarcu Mountains, something large is on the move. Trainee ranger Adrian Miculescu signals to his group of visitors to hunker down. Camera settings are adjusted, heart beats rise, lenses scan the nearest thicket.

Brushing aside pine branches, a massive head emerges, eyes small yet bright beneath a mop of shaggy chestnut hair. Behind curved horns and a heavily muscled neck, the animal's broad back rises to a hump. Lifting its nose to the wind, the huge male bison samples the air warily, grunts and retreats back into the forest.

There was once a time when the European bison - the continent's largest land animal - ranged across western, central and southeastern Europe, right up to the Volga River, in Russia, the Caucasus and beyond. Inhabiting forests from Scotland to Siberia, fully grown males had no natural predators.

Yet just as the American bison was hunted to the very edge of existence in the 19th century, its European relative has suffered a similar, if more prolonged assault.

Prized for its meat, the bison had disappeared from much of its original range by the Middle Ages. A sustained decline followed, which saw the last wild Polish bison poached in 1919, and the last of its kind in the Caucasus fall in 1925. At that point, less than 60 European bison remained, in zoos and private parks.

It is from this limited gene pool that the European bison has now made a tentative comeback, with breeding programmes across the continent boosting the current stock to about 5,000 animals. With a population dwarfed by that of its American counterpart (there are about 500,000 bison in North America, although most of those have been cross-bred with cattle), the European bison remains rarer than the white rhino.

Efforts to reintroduce this majestic animal are part of a far larger initiative to turn back Europe's ecological clock, to make the continent wild again.