River Otter Essay

River Otter

Though not commonly observed in the wild, the river otter, Lutra canadensis, is a fairly familiar animal to most people. Its original range covered most of North America. It is one of the larger of the weasel tribe, its recorded weights running over twenty pounds, though I do not have at hand weights of the large Alaskan sub¬species.

The otter is agile, fluid in its movements as the water that is its favorite element. Yet on the land it is not as light on its feet as the weasel or marten and seems almost to plow through the snow. This is revealed by its tracks, which sometimes appear in a snowy trough. Characteristic, too, is the long mark in the snow where the otter has slid. Coasting is enjoyed occasionally by the mink, but the

There are usually air holes in the ice through which mink or otter can go in or out. Such holes, leading down through the covering snow and through an opening in the ice, have been described for the mink. Those used by otters are of course correspondingly larger.

The “slip,” as the otter travels in the snow, may be a foot or more wide, and is easily distinguished from the one made by mink. However, it should be remembered that a beaver will also come out of the water into the snow, and will make a wallowing trough. But, a close study should reveal some sign of the beaver’s large webbed hind feet. In the distance I have seen such a beaver mark on a snowy bank and mistaken it for that of an otter.

The porcupine is another animal that will wallow out a trough in deep snow. A close study should reveal some marks of the stiff hairs of the tail, and the toed-in foot marks. Of course there will be no slide. When there is doubt in such cases, follow the trail a distance to find some indication in a better spot of snow, or to see whether the animal climbed a tree, or did any other un-otter¬like

Cook published a significant experience that took place in December 1938, in New York State, when he was walking up Kinderhook Creek: “Glancing upstream, I noticed a dark object floating down in midstream. As it came nearer, it resolved itself into an otter. I watched the animal come down through two riffles, with head well up, body and tail held stiff and hind legs wide apart, very obviously enjoying a free ride. It skillfully avoided boulders and kept itself in the swiftest current.”

There is another sign that I have not seen, but which is described by Grinnell, Dixon, and Linsdale (1937). To quote them:

River otters have a unique way of twisting up tufts of grass to mark selected points where scent from their anal glands is regularly deposited. A. H. Luscomb, who has long been acquainted with the river otters in the Suisun Bay region, says that he knows of several such rolling places and “sign heaps” that have been visited regularly by almost every otter pacing along a certain slough during a period of fourteen years. It is thus likely that otters, like beavers, maintain certain signposts and that these stations are visited by any adult otter that passes through the neighborhood.

Otter droppings may be found at these signposts, or on logs or rocks adjacent to or extending out into the water. The boat concessioner at Yellowstone Lake sometimes has been troubled by the otters thus defiling the rowboats during the