We have plenty of river otters in the Interior and even more in the central and southeast coastal areas.
Otters can leave some strange looking trails in the winter when they spend a lot of time pushing off and sliding on their bellies. This may be an efficient method of travel for them rather than trying to bound through the deep snow. The tracks shown above are old (been snowed in and appear soft and covered up). The otters above were pushing off-sliding-bounding, pushing off-sliding-bounding, over and over and over.
Otters come and go from land to water, taking advantage of cracks in the ice or areas that don't quite freeze.
Be careful on the rivers. This otter was getting into the river somewhere beneath the snow, which means there is some open-water covered over by the snow. If you step on it you will go through. Yes, been there, done that.
This is important to know because other animals, such as mink, may also occasionally belly slide.
When an animal is loping or bounding you will see space between the groups of tracks. In the photo on the left the otter was loping and leaving a distinct tail drag in the snow every time it landed.
Front tracks can be about 2 1/2 to 3 1/2 inches long by about 2 to 3 inches wide.
The hind tracks can be from 2 1/4 to 4 inches long by about the same in width, depending on the otter.
Notice the bulbous toes and asymmetry of the tracks (especially the hind).
Keep an eye out for other otter sign such as scat. They have certain areas where they will hang out and deposit scat and scent mark. These are called loafing sites, rolls or latrines.
Otter scats are amorphous, can be slimy or gooey, and usually have fish scales in them.