Thousand Islands level year-round, and support at least two living trees. The Thousand Islands archipelago is located at the outlet of Lake Ontario at the head of the Saint Lawrence River. The region is bisected by the Canada–United States border and covers portions of Jefferson and St. Lawrence counties in the U.S. state of New York, in addition to parts of the United Counties of Leeds and Grenville and Frontenac County in the Canadian province of Ontario. Geologically, most of the islands are located where a branch of the Canadian Shield runs south across the river to join with the Adirondacks. The
North American river otter length. A shorter trachea may improve air exchange and increase lung ventilation in diving mammals. Most mustelids, including otters, have specialized teeth, including sharp canines and carnassials that inflict lethal bites to prey. Also, North American river otters have large molars used for crushing hard objects, such as the shells of molluscs. An adult North American river otter has a total of 36 teeth. Additional premolars may be present. The dental formula is . North American river otters are active year-round, and are most active at night and during crepuscular hours. They become much more nocturnal in the spring, summer,