River Otters (Lutra canadensis) are semi aquatic animals with webbed feet and fairly streamlined bodies. Their colors range from brown to grey/silver in color. Full grown adults usually weigh approximately 20-30 lbs. Males are almost always larger than females. Including their tail, they can be well over 4 foot long and possess surprisingly sharp claws and teeth.
They’re highly skilled hunters, easily able to catch salmon and other fast swimming predatory fish. When not directly in the water, River Otters will also scavenge for shellfish such as clams, crabs, or even scraps left on docks of marinas and boathouses. Many people do not ever see River Otters, yet they are actually pretty common throughout all of Washington State. In fact, most rivers, ponds, streams, rivers, lakes, and bays throughout the Pacific Northwest hold abundant populations of these critters. They can even thrive in salt and brackish water areas as long as a steady food source is available. They’ll commonly feed on bird/fish eggs, reptiles, amphibians, oysters, mussels, muskrats, mice, and other small mammals.
River Otters are very crafty at making dens. In the wild they usually prefer a hollowed out log, log jams, piles of driftwood, or bank dens that have been abandoned from beavers, muskrats or other critters. More often than not, these dens are very hidden and usually never seen by humans. In more urban environments, they’ll take up residence or make a den a half a mile or more away from water. They’ve been found under homes, in boat houses, and even in duck hunting “blinds”.
Once they’ve taken up residence to a structure, usually trapping is the only way to successfully evict/remove them. Otters are pretty good at climbing short fences and even better at digging to go underneath fences/structures. Cage traps can be strategically placed to catch them along these travel routes. It is optimal to seal off all other access points than where the trap(s) will be placed, forcing the River Otter(s) to have to go into the trap(s) and then be removed from the property.
After a River Otter issue has been dealt with it is optimal to seal up the access point(s) as soon as possible. This is usually done with hardware cloth (“wire mesh”) and staples and/or screws. They’re usually living in family groups so it’s imperative to do a thorough job securing any points of entry. It is not uncommon for Otters to return to a spot year after year (if not caught in traps). Unfortunately not many deterrents are successful for these critters so trapping/exclusion is very crucial!
