Scent is an important medium of communication for many animals, and the river otter, Lontra canadensis, takes it to a new level. It seems to make a celebration of elimination. I placed a trail camera on a lake shore in Massachusetts, where otter sign abounded. There were many fish scale filled scats, some carefully placed on mounds of debris and some directly on the sand. The activity was particularly intense on a 15 foot length of shoreline, where I stationed the camera, and there was additional scatting intermittently in either direction. I envisioned a raucous party of scatting, rolling, and grooming. When I checked the camera 5 days later, I was not disappointed. The video below of a group of river otters scent marking, consists of clips from just those few days, so clearly this is an important area for them.

A North American river otter, Lontra canadensis, pauses on the shore.

What struck me as I watched the clips, is that scatting appears to be a major social event for this trio. The video was captured in spring, so the animals could either be a group of males or a mother and 2 young of last year.

The proximate cause of this behavior may be that rolling around feels good, and doing it with friends is fun. The ultimate cause remains a matter of debate. It could be that it gives the animals a “group smell” and marks the shoreline as belonging to them – a way to tell other otters that this area is occupied. The problem is that latrine activity is seasonal, peaking in late winter through spring, falling to nil in summer, peaking to a much lesser degree in fall, and diminishing again in winter. Shoreline scats may provide information about sexual status, but if that’s the case, I’m not sure why group members would roll in each other’s scat.

River Otters Scent Marking Video

Watch the video and notice how they gather up debris into a mound, then paddle the hind feet and wag the tail vigorously, as they  eliminate. Why so much fanfare? Maybe that will be the topic of a future post. I hope to keep this camera in place throughout the summer, so we’ll be seeing more of this group.

Notice that one of the otters appears to have only one eye (evident on the night time clips). That will make it easier for us to see differences in the social structure of this group.

Want to see photos of river otter scats, tracks, etc.? Check out this article on River Otter Tracks and Sign.