Elevations occupied by the Sierra Nevada red fox are also an area of current research. Oregon detections have occurred between 4900 and 6500 feet, though observations of Cascade red fox in Washington suggest lower elevations may be accessed during dispersal. John Perrine's study on Lassen Peak, using 144 baited motion-sensitive cameras from 1997 to 2002, found no foxes below 4520 feet. Historically, Grinnell's 1937 survey found occurrence from 4500 to 11,500 feet in California.: The fox was initially described in 1906 as occurring above 6000 feet in the high Sierra.: