The otter was recorded on a camera near the Nieuwkoopse Plassen, an area of lakes and marsh between Amsterdam and Rotterdam.
The otter is thought to have died out in the Netherlands in the 1980s, but since 2001 there has been a programme to reintroduce them in the north of the country.
A spokesman for the natural heritage group Natuurmonumenten said the return of the otter shows the water in the Nieuwkoopse Plassen is of good quality. ‘The otter is at the top of the food chain and the fact he is back says something about the quality of the nature,’ the spokesman said.
The cameras were placed because faeces had been spotted in the area which experts thought may have come from an otter.