The species was brought to extinction in Slovenia in the 18th century, but its presence in Slovenia has been increasing in the last 15 years.

The large rodents have arrived from Croatia upstream the Sava river, spreading to east and south-east Slovenia through Sava's tributary Krka.

They have populated almost the entire Krka basin, including the lower parts of its tributaries, and there are plenty of signs of their activity, Andrej Hudoklin of the Nature Conservation institute has told the STA.

The animals are obviously not afraid of humans, as a group of beavers is building a lodge in the centre of Novo mesto, the largest city along the Krka.

Biologists estimate that the beaver population in Slovenia currently numbers around 300 specimens.

Their number is expected to increase rapidly, and this issue should be discussed at the national level to take appropriate measures, Hudoklin warned.