The shaggy giants have arrived in the Jura!

Wisent Thal" project

Would it be possible to reintroduce free-ranging bison (Bison bonasus) to the Swiss Jura? - This is precisely the question that the "Wisent Thal" association wants to answer with a well-monitored and supervised test herd. After many years of preparation and approval procedures, the pilot project has now been definitively launched.

The Zurich Wilderness Park supports the "Wisent Thal" project

On Thursday, September 15, animal keepers from the Zurich Langenberg Wilderness Park brought the first five bison to Welschenrohr in the canton of Solothurn. There, in the district of Thal, there is a fenced-in area, currently around 50 hectares in size, for this ambitious project. "It was an emotional moment for us too," explains Martin Kilchenmann, Head of Animals at Zurich Wilderness Park. "We are delighted to be part of this unique species conservation project as a partner of the "Wisent Thal" association."

Among other things, Zurich Wilderness Park will continue to maintain the dossiers in the international animal database for the animals in Welschenrohr and advise the project on animal care issues. The Zurich Wilderness Park and its animals have been involved in the European conservation breeding program for bison for many years. The aim of this program is to maintain a genetically broad and healthy population in captivity so that suitable animals can be made available for reintroduction projects. At the same time, suitable habitats need to be preserved and protected.

European bison almost extinct

In 1927, a poacher shot the last free-living bison in the Caucasus. Only a dozen animals capable of reproducing remained in European zoos. In the meantime, the population of "European bison" has grown back to over 8,000 animals, but the species remains "potentially endangered".

As all bison living today descend from the same 12 ancestors, it is important that the herd in the Solothurn Jura is carefully selected. The animals should have as broad a genetic basis as possible. To this end, the breeding program has access to the animals' pedigrees and additional genetic analysis data from tissue samples.
The starting herd in the Solothurn Jura currently consists of one bull, three bison cows and one calf. The females are half-sisters born in the Zurich Langenberg Wilderness Park; the bull originally comes from the Bruderholz Zoo in Winterthur and has been living in the Langenberg Zoo since fall 2021. The adult animals are all between three and five years old and are therefore still considered almost "adolescents". European bison can live up to 24 years, while bulls rarely live longer than 16 years.

The largest land mammal in Europe

The European bison is the largest and heaviest land mammal in Europe. It grows up to two meters high and three meters long. An adult male can weigh over 800 kilograms, females weigh around 550 kilograms.
The animals live in mixed and deciduous forests with moist clearings and well-developed undergrowth, forest-meadow mosaics and forest steppes. They are active during the day and at night and form herds of 5 to 40 individuals. "As relatives of domestic cattle, they are ruminants and prefer to eat leaves, small shoots and bark," explains Martin Kilchenmann.

Due to their food requirements of up to 60 kilograms a day, wild cattle influence the vegetation. They preserve meadows and heaths by protecting them from scrub encroachment. In forests, they provide clearings and sunlight down to the ground. In this way, they contribute to biodiversity and are therefore sometimes referred to as "landscape gardeners".

Bison herds as a danger for hikers or farmers?

Over the next five years, a scientific monitoring group will investigate and document the animals' choice of food and the herd's behavior towards people, livestock and other facilities.

During the first two years, the animals will live in a fenced-in area of half a square kilometer, after which the enclosure will be doubled in size. In this second phase, several hiking trails will also run through the enclosure.

A decision will not be made until 2027 as to whether the bison herd will be allowed to roam completely freely and without fences in the Jura in future. "I'm very excited about the coming years," explains Kilchenmann. He is absolutely open-minded. "If society decides that bison are unacceptable, we have to accept that, but if the trial can convince the majority that it is possible and the bison could once again live as wild animals in this country, as they already do in other European countries, that would be a remarkable step for species conservation."

Link to the "Wisent Thal" association

High-resolution images and film footage can be found in the ZIP file below