For a number of decades, northern river otters were not spotted in the Bow Valley around the town of Banff. I saw my first otter several years ago. Since then, there have been more and more sightings. Last month in this same area, within 24 hours, I saw five otters and evidence of two more. It is very likely that there are far more than seven. This could be in large part due to the increase in the beaver population in the same area over the last several years, providing more wetland habitat.
It has been noted that if beavers are trapped out of an area, otter numbers tend to drop. Otters are found near waterways, swamps, marshes, bogs, lake shores, and marine coasts across much of North America. Their top swimming speed is 11 km/h, whereas on land, they can run at speeds between 24-29 km/h, either running or running and sliding.
They can use a variety of temporary dens within their home range, created by other species, often beavers, muskrats, foxes, and other mammals. Alternatively, they use natural sites that are adapted by otters, such as rock crevices, caves, logjams, undercut riverbanks, cavities in tree roots, and fallen wood debris. It is rare for otters to create their own burrows. Their preferred den sites typically have a submerged entrance, such as bank burrows or abandoned beaver lodges. Birthing dens tend to be a safe distance from the water to avoid the danger of flooding. During winter, snow cavities can also be used as den sites.
