Three years ago, the first stone marten was discovered in Sweden, near Bromölla.

Since then, eight stone martens have been found in the Bromölla area and new DNA analyzes indicate that all are descended from one and the same female.

- Our theory is that a pregnant female came here in a truck from Europe and that the driver stopped for a coffee break in Bromölla and that she then jumped out and gave birth to her litter here, says Per-Arne Åhlén.

"Gnawing on electrical cables"

The new mammal species for Sweden is described in Europe, where it causes billions in damages.

- Their hobby is to gnaw on electrical cables in cars, says Per-Arne Åhlén.

In the clip above, Per-Arne Åhlén tells more about the stone marten and how it can cause fires.