Species reintroduction is the release of a species into the wild. Animals that were born in zoos are released back into the wild (usually at a young age) under the supervision of a team of biologists on location in the field. The animals are released in areas that belong to the species’ original habitat but where the animal is locally extinct or where its numbers have declined dramatically. A species reintroduction project often sounds a lot simpler than it is. In cases where reintroductions are possible and responsible, Burgers’ Zoo is more than happy to cooperate! This time: the otter and beaver are back in The Netherlands.
We can no longer imagine it, but there were no otters or beavers in the Netherlands for a long time. In 1826, the last wild beaver in the Netherlands was caught in the river IJssel and beaten to death. From that sad moment on, the beaver was officially extinct in our country. The otter lasted somewhat longer, but because of persistent prejudices—otters supposedly emptied entire rivers of fish and thus threatened the livelihood of Dutch fishers—they were intensively hunted until the 1960s. In 1989, the last otter in Friesland was run over, making the otter officially extinct in our country.
Fortunately, an awareness slowly developed in the Netherlands that the beaver (and later also the otter) should return to our country. In 1988, a bever reintroduction project was initiated. Beaver pairs from the Elbe area in the former GDR (East Germany) were released into the Biesbosch between 1988-1991. After this successful reintroduction, beavers were also released in the Gelderse Poort, a nature reserve in Gelderland, in 1994.
Burgers’ Zoo veterinarian Henk Luten actively cooperated in this project by giving all East German beavers a preventive medical examination and fitting them with a transmitter before release. Henk Luten is also the veterinarian at Wageningen Environmental Research (Alterra). This scientific organisation contributes to realising a high-quality and sustainable green living environment through expert and independent research. Luten remembers how razor-sharp the chiselled front teeth of these rodents are—a scalpel is nothing by comparison! They are spectacular, charismatic rodents. They have a crown-rump length of 70 to 100 centimetres and weigh up to 30 kilograms, making them the largest rodents in Europe.
In 2002, it was also time for the otter to return to our country. Some of these otter pairs also came from Eastern Europe. Both projects—the reintroduction of the beaver and the otter—were carried out by Wageningen University (Alterra) and have both been under the strict supervision of the Animal Experiments Committee (DEC). The otters were chipped and fitted with a transmitter by Henk Luten. Afterwards, they were released into the Weerribben-Wieden nature reserve. Burgers’ Zoo facilitated both projects by making an operating theatre available free of charge and temporarily stationing the animals in Arnhem until they could be released into the wild.
Meanwhile, the beaver and the otter are doing well again in the Netherlands! Beavers have been spotted in almost all Dutch provinces. At the end of 2019, the total number of beavers in our country was estimated at 3500 animals. Provinces with a lot of beavers are Gelderland, Limburg, Noord-Brabant, Zuid-Holland and Flevoland. Fortunately, the otter population is also increasing. In 2020, the number of otters in the Netherlands was estimated at 450 animals, whereas a year earlier, it was still 360. The otter has spread across a large part of the North-Eastern Netherlands. The animals move easily via ditches and canals, partly over land, expanding their species distribution. This practical example also shows how a zoo can actively contribute to successful reintroduction projects, even in our own country!
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