The only place to see an aurochs in nature these days? A cave painting. The enormous wild cattle that once roamed the European plains have been extinct since 1627, when the last survivor died in a Polish nature reserve. But this could soon change thanks to the work of European preservationists who are hoping they can make the great beast walk again. If they succeed through a combination of modern genetic expertise and old-fashioned breeding it would be the first time an animal has been brought back from extinction and released into the wild.
The aurochs was a massive creature, standing more than six feet tall at the shoulder and weighing more than a ton. It had forward-facing horns and a white stripe running down its spine. The prehistoric animal was domesticated about 8,000 years ago, but some aurochs also remained in the wild until the end of the Middle Ages, when scientists believe they became extinct due to overhunting and loss of habitat.
The hope for its resurrection now lies in its tame descendants, domesticated cattle. Here's how the process is expected to work: Scientists will first scour old aurochs bone and teeth fragments from museums in order to glean enough genetic material to be able to recreate its DNA. Researchers will then compare the DNA to that of modern European cattle to determine which breeds still carry the creature's genes and create a selective-breeding program to reverse thousands of years of evolution. If everything goes as planned, each passing generation will more closely resemble the ancient aurochs. "Everything will be put together in a genetic mosaic," says Donato Matassino, head of the Consortium for Experimental Biotechnology in Italy and one of the scientists involved in the project. "Once we have all the roads, we'll try to follow them back to Rome."
Stichting Taurus, the Dutch preservationist group leading the project, is hoping a reborn aurochs could help restore the European countryside to a more natural state. To that end, the group would eventually like to replace the domesticated cattle that currently graze in Holland's nature reserves with the recreated wild cattle. "The aurochs was part of an ecosystem," says Henri Kerkdijk, manager of the project. "If you want to recreate the flora of the ecosystem, you also have to recreate the fauna." The idea came to Kerkdijk during a trip to Africa, where he was struck by the abundance of giant herbivores, even in areas where people were living. "It just bothered me that we don't have that in Europe anymore," he says. His group has already introduced English Exmoor ponies the closest living representatives of the wild horses painted alongside aurochs on cave walls to the Netherlands' nature reserves. "You could also talk about recreating the giant deer," Kerkdijk says. "But there, we don't have a modern animal to work from."
The current effort isn't the first attempt to resurrect the ancient cattle. The aurochs played an important role in early German culture, and in the early 20th century the Nazi government funded an attempt to breed them back as part of its propaganda effort. The result, known as Heck cattle, may to some extent resemble the ancient aurochs, says Kerkdijk, but they're genetically quite different. "We want a breed that resembles the aurochs, not only in phenotype, but in genotype," he says. Heck cattle, for example, are more aggressive than aurochs because they were bred, in part, using Spanish fighting bulls. "They will attack without a prior threat display," says Kerkdijk. "When I'm in Africa, herbivores won't attack me. They give some type of warning: Back off, one step further or you're dead meat."
Other groups are also trying to bring different animals back from extinction through breeding. In South Africa, scientists are attempting to recreate the quagga, an extinct subspecies of the zebra, and in the U.S., breeders are trying to bring back a giant Galápagos tortoise that was killed off in the 1800s a process that could take close to a century.
Back-breeding has an advantage over cloning in that it creates a whole population, rather than just an individual animal. Last year, Spanish scientists used cloning to successfully recreate an ibex that disappeared in 2000, and in Poland another group is trying to clone the aurochs using DNA from bone and teeth samples. But for a species to survive once it's brought back to life, it must have enough genetic variability to reproduce. "A population needs to be adaptive," says Johan van Arendonk, a professor of animal-breeding and genetics at Wageningen University in the Netherlands, adding that the Dutch project probably needs to produce at least 100 animals to succeed in the long term.
That's not the only obstacle. Recreating the aurochs from modern cattle won't work if any of its DNA was lost as breeds split apart, experts say. And it will take a lot of time. "The only way we can make recombinations is by having the animals produce a new generation," says van Arendonk. "It's still a very open question if it all can be done."