Name of animal: River Otter (Lontra canadensis).
General description of the track: Tracks of a river otter are about the diameter of a tennis ball with five toes on both the front and rear. Faint webbing on the rear paws are only visible in the most detailed tracks. The river otter’s bound leaves a unique pattern of tracks diagonal to the direction of travel. Also look for other sign such as pointy-ended scat that is often a whitish color, and “middens” — heaps of refuse — composed of urchin and other shell pieces above the tide line.
Where and when to look: These tracks can be found year round as river otters can be found working along streams, beaches and lake shores.
Lookalikes, and how to tell them apart: In Southeast Alaska the weasel family includes ermine, mink, marten, river otter, wolverine and sea otter. (The skunk hasn’t made it yet!) They all have five toes on both the front and hind paws. Developed by naturalist Greg Streveler, the “rule of thumb” is a helpful way to differentiate weasels: tracks the size of a thumb nail belong to ermine; mink tracks stretch from the tip of the thumb to the first knuckle; marten and river otter stretch to where the thumb meets the hand, and anything larger belongs to the wolverine.
More about the river otter: The weasels are a family of hunters who each specialize in different habitats. Mink overlaps the most with river otter, while the sea otter rarely comes ashore. The wandering wolverine prefers alpine while the marten prefers coniferous forests. The ermine is the least specialized habitat wise, but its small size allows it to hunt in tight spaces. A paper presented at the recent wildlife conference by Howard Golden and Merav Ben-David claims that middens of coastal otters in south central Alaska are concentrated on bedrock points and convex shorelines. Because they are easily trapped, default refugia, or hard-to-reach places may be important to long-term survival.
• This tracks feature appears every other week during winter months and is compiled by members of Discovery Southeast, a local nonprofit offering a variety of programs for local youth aimed at educating and engaging students in their outdoor world. For more information on the organization, go online to discoverysoutheast.org.