With fewer than 3,000 European bison in the wild, the massive mammal is more threatened than the black rhino — which is why its return to wilderness areas across Europe is so incredible. (In case you are wondering about that math, there are more than 5,000 black rhinos alive today, according to the World Wildlife Fund.)

The European bison, also known as a wisent, once thrived in the countryside in most of Europe. But the massive beast, weighing as much as 2,000 pounds or more, was hunted to extinction in the wild by 1919.

With the help of 54 animals kept in zoos, the population has slowly grown to 3,000, reports Rewilding Europe, a Netherlands-based group focused on increasing the number of bison and many other animals in the wild. They have their work cut out for them: currently, there's not one long-term viable bison population in the wild.

The group plans to establish at least five herds of more than 100 animals by 2022, and an overall population of more than 1,000 bison by 2032.

herd of bison in the snowBecause the European bison eats so much and grazes on such varied vegetation, its impact on the ecosystem is substantial. (Photo: Grzegorz Lesniewski/Rewilding Europe)

Although the European bison has traditionally lived in the forest, it also spends time in open areas. It is primarily a grass eater, but it also grazes on bushes, brambles and trees, eating as much as 130 pounds a day.

Eating that much has a "real impact on the vegetation, keeping open lands open and creating a mosaic savannah landscape," says Rewilding Europe. "Besides grazing in the front end, it tramples in the middle, wallows in mud holes, rolls in sand pits that it has kicked up, and then fertilizes from its rear end. All of which has great importance to the variety of Europe’s ecosystems."

A challenge with reintroducing the bison is that few people are familiar with the endangered animal and therefore fewer places are willing to accept them.

Rewilding Europe has embarked on a communications campaign to reintroduce the bison to the public, according to the group's website.

"We are working to make the European bison a living symbol for a new, modern relation between man, wild nature and wildlife in Europe."

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.