A conservation charity is making improvements to Surrey's riverbanks in an attempt to boost the number of otters in the county.
Surrey Wildlife Trust said there were "positive signs" otter numbers were increasing in the west of the county.
The trust is hoping to attract even more by restoring riverbanks and building more artificial otter homes.
The mammal was once thought to be close to extinction due to hunting and the use of certain pesticides.
A trust spokesman said: "The news that they are now trying to re-colonise Surrey is a sign that, after years of work, our rivers are becoming clean and healthy again."