The San Pedro River, partially rerouted underground by an 1887 earthquake, may not look like much, but it sustains an impressive array of flora and fauna and makes for great hiking and birding. To maintain this fragile creekside ecosystem, 56,000 acres along the river were designated a protected riparian area in 1988. More than 350 species of birds come here, as well as 82 mammal species and 45 reptiles and amphibians. Animals from long ago—including woolly mammoths and mastodons—also make their former presence here known through the area's massive fossil pits; in fact, many of the huge skeletons in Washington's Smithsonian Institute and New York's Museum of Natural History came from here. As evinced by a number of small, unexcavated ruins, the migratory tribes who passed through thousands of years later also found this valley hospitable, in part because of its many useful plants. Information, guided tours, books, and gifts are available from the volunteer staff at San Pedro House, a visitor center operated by Friends of the San Pedro River (www.sanpedroriver.org).