Could European landscapes one day be teeming with giant cattle that have been extinct for close to four hundred years? They could, if projects underway to reintroduce the aurochs succeed.

The oversized wild cattle known as the aurochs died out in the 1627, but the oldest known subspecies of its kind dates to some 2 million years ago. The animals lumbered and grazed across Europe (as well as Asia and North Africa) for thousands of years and were among the biggest herbivores of their day, standing anywhere from 5 to 6 feet tall, weighing from 1,500 to 3,000 pounds.

Two programs are working to bring them back: The Tauros Programme and Operation Taurus. Each is employing a process called back-breeding that, if all goes according to plan, will essentially breed the animal back into existence.

Aurochs descendants live on today as domestic cattle, and the back-breeding process for the ancient grazer involves using modern relatives of the aurochs – particularly those breeds known to have many of the extinct animal's characteristics – and, over several generations, selectively breeding them until their offspring become as close as genetically possible to the original aurochs.

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The reason it would be beneficial to have herds of aurochs roaming free, the programs argue, is that the large grazers can serve a key ecological role in maintaining and encouraging the biodiversity of Europe's landscapes. When such big grazers graze, their appetites help shape the land, creating open spaces and varied landscapes that help a wide variety of other species succeed in the same neighborhood.

Of today's cattle, the Tauros Programme notes: "none of the current breeds is the optimal grazer for wilderness areas, especially not with big predators around such as wolves, in the bigger European wilderness areas."

The ultimate goal of the Tauros Programme is for there to be herds of new proto-aurochs – around 150 per group – living in self-sustaining populations in Europe by around 2025. The program has bred more than 100 animals so far.

Operation Taurus, for its part, has bred some 300 calves from back-breeding, as it tries to get as close as possible to the real thing. "I don't think we'll ever be able to create an animal that is 100 per cent like the aurochs, but we can get very close," the operation's Donato Matassino told The Telegraph.

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