An early 1875 exploration of the Black Hills found only northern red horse suckers and dace in Spearfish Creek; trout were not indigenous to the Black Hills and were introduced from Colorado in the late 1800s. Today, Spearfish Canyon offers excellent fishing opportunities, and Spearfish Creek is one of the premier trout streams in the Black Hills. Rainbow trout naturally reproduce in Spearfish Creek, the only place in South Dakota where such reproduction has been documented, and brown and brook trout also reproduce naturally throughout the Spearfish Creek watershed. The American dipper, a small gray bird native to the Black Hills, was once found in several streams in the northern Black Hills but is now largely confined to Spearfish Creek and nearby Whitewood Creek; it lives year-round in or near water, nests above water on cliff faces or under bridges, hunts aquatic insects in shallow water, and survives the cold, wet environment with thick down feathers and water-repellent outer feathers. Beaver dams raise water tables and slow stream flow, creating habitat for many plants and animals; French-Canadian trappers seeking beaver pelts were the first Euro-Americans to enter the Black Hills in the 1700s, the beaver population declined sharply by the late 1800s, and protection efforts in the early 1900s allowed it to recover. Today, beaver dams stand alongside human-made diversion dams that control flooding, generate electricity, and provide water to Spearfish. More than 500 plant species are known in Spearfish Canyon, many of them used by indigenous tribes for food, ceremonies, or medicinal purposes, with cool shaded drainages and riparian areas supporting especially diverse plant life. Ornate plants are plentiful, True Forget-Me-Not is an introduced species that grows directly in Spearfish Creek, many lichen and moss species are common, and many Black Hills plants cannot be found elsewhere for hundreds of miles.