After nearing extinction in Europe in the early 20th century because of hunting and shrinking habitats, large carnivores like the gray wolf, brown bear, lynx and wolverine are thriving once more.

So say the results of a study carried out across the continent, except Russia and Belarus, by an international team whose report was published Thursday in the US journal Science.

"The total area with a permanent presence of at least one large carnivore species in Europe covers 1,529,800 square kilometers (roughly one-third of mainland Europe), and the area of occasional presence is expanding," the authors wrote.

The study involved 76 scientists examining 26 countries.

Brown bears were the most numerous of the four species, with nearly 17,000 specimens and a permanent presence in 22 countries.

The gray wolf came next, with a population of more than 12,000 scattered across 28 countries, followed by the Eurasian lynx, 9,000 of which were to be found in 23 countries.

Wolverines were the scarcest of the four, with an estimated 1,250 of the cold-climate creatures found in three Nordic countries: Norway, Finland and Sweden.

Although most populations of these large predators have been on the rise or stable in recent years, some are on the verge of extinction, such as the gray wolves of Spain's Sierra Morena region, the Pyrenees bears or the lynx found in the Vosges region of France.

All four species of carnivores live and reproduce mostly outside protected areas, such as national parks, in human-dominated landscapes.

- Conservation policies work -

Their numbers suggest that they can coexist with humans in areas dominated by the latter, testifying to the success of European Union conservation policies, the authors wrote.

For instance, Europe today has twice as many wolves as the United States even though its territory is half the size of North America and its population twice as dense.

"Our results are not the first to reveal that large carnivores can coexist with people but they show that the land-sharing model for large carnivores (coexistence model) can be successful on a continental scale," the study stated.

In the US, by contrast, protected species often live far from human-inhabited ones, such as wolves of Yellowstone National Park.

The researchers said several factors explained the vitality of Europe's populations of large carnivores, including the replenishing of stocks of prey such as deer and wild boars, which provides them with ample food.

They also cited an exodus of people from rural areas in the 20th century, which allowed wolves, bears and lynxes to expand their territories.

But the report mainly attributed the success to laws aimed at preserving species of wild animals and their habitats, such as the Berne convention of 1979.

Test tube likely last hope for dwindling white rhino species
San Diego (UPI) Dec 19, 2014 - With this week's news that the San Diego Zoo had lost one of its two northern white rhinos, the pressure to save the species from extinction became even greater. As natural reproduction is unlikely -- near impossible, in fact -- producing a test tube baby may be the only way to save the northern square-lipped rhinoceros (Ceratotherium simum cottoni).

There are now only five specimens left on planet Earth, and researchers around the world are scrambling to figure out a way to prolong the species' existence -- and hopefully jumpstart a breeding program. Four of the five left are females -- one in San Diego, one in the Czech Republic and two in Kenya. The last two are joined at Kenya's Ol Pejeta Conservancy by the world lone male northern white rhino.

None of the five rhinos are wild in any traditional sense. But the three remaining Kenyan rhinos did adopt some of the behaviors of their wild (late) relatives -- like nocturnal feeding -- after they were moved to the preserve in 2009 from their previous home in the Czech Republic. Two years after the move, two of the then four rhinos were seen mating. But the pregnancy didn't take.

Scientists have considered in-vitro fertilization, but the process of artificially inseminating a massive mammal would be dangerous and expensive -- with little guarantee of success.

"You're dealing with semi-wild, what, two ton animal?" Richard Vigne, the CEO of Ol Pejeta, told NPR. "Which is very different than dealing with completely domesticated cattle."

The last option is the test tube. Researchers are now thinking of fertilizing an extracted white rhino egg with with frozen northern white rhino sperm. The impregnated egg would then be implanted in the surrogate womb a southern white rhino, a genetically unique subspecies.

The southern white rhino was once endangered too. Like the northern white rhino, it is wanted by poachers for its horn, which is ground into a powder and sold as a sort of magic elixir in Asia -- used to treat all sorts of remedies, from nosebleeds to strokes.

Southern white rhinos were thought to be extinct by the end of the late 1800s, but a small herd of 20 was located in Kwazulu-Natal, South Africa in 1895. The rhinos, immediately collected and protected, rebounded thanks to an international breeding program. Today, there are nearly 20,000.

But while southern white rhinos were essentially taken right off the savannah and into protected preserves, the remaining northern white rhinos have been living in the confined and artificial habitats of international zoos. Vigne says he thinks females shut down their reproductive capabilities after a prolonged period confinement.

Researchers are expected to meet in Kenya in January to further discuss the feasibility of in-vitro and test tube fertilization.