Their home ranges are only 3-10 miles in length depending on habitat quality and the time of year. A study in Missouri found that otters on one fish and wildlife area had home ranges 7-48 miles long and reached an average density of one adult per 5 miles of shoreline. As many as nine otters have been spotted together in Illinois. Smaller groups of 3-5 are more common, and usually consist of a female and her offspring. Examples include logjams, oxbows, pools below dams or spillways, and springs or riffles that stay free of ice all winter.
Otters usually follow watercourses, but cut across land if it's more convenient.
Some crossings are used so often they have worn trails. Areas visited frequently or for long periods of time are fairly obvious. Otters tend to drag large fish onto the shoreline or a logjam to dine. Scales, heads and other uneaten parts are left behind. Small piles of leaves or grass are sometimes raked into a mound and marked with droppings or a thick yellowish fluid from their anal glands.