Otters are medium-large sized carnivores, with flattened heads and a broad muzzle. They have dark brown fur, slightly lighter than the American mink. When otters swim, they use all four legs underwater, leaving only their head visible on the surface. This creates a bow wave (large V-shaped wave).
Otters are difficult to spot, but they often leave their spraint in full view. Have a look on rocks or under bridges on your local river. Spraints are full of fish bones and smell like jasmine tea! Note: otter spraint gets washed away when rivers are full, so don’t try to survey if it has recently rained.
Otter tracks can be found in sand and mud (and snow) alongside rivers and streams. They are five-toed, but often only four toes appear in the print (see image below). The large, round prints (5-7cm in width, 6-9cm in length) are often pushed deep into the clay providing clear ID field signs.
At this time of year otters will be going about their normal business. The best times to try and spot them are at dawn (ideally around half an hour before sunrise and up to an hour after sunrise) and dusk (around an hour before it gets properly dark).
For more general information factsheet on otters including distribution and habitat information and their conservation status click here.
Download a field signs pdf here.
If you have a particular interest in otters, or you may have found a dead otter and want to let someone know about it, you may want to take a look at Cardiff University’s Otter Project. The Otter Project is a long-term environmental surveillance scheme, using otters found dead to investigate contaminants, disease, and population biology across the UK.
To record otter signs or sightings while you’re on a walk or bike ride why now download the Mammal Mapper app?
Alternatively, log signs or sightings on our record submission page here.