Across the Valley on its west side, at the foot of the sparsely settled Diablo Range, can be found the remains of one of the state's oldest roads, El Camino Viejo, an 18th-century Spanish cart track. This dry region used to look like what writer Marc Reisner called the "Serengeti of North America." In the 19th century, it was populated by herds of ruminants that thrived on the semiarid grasslands: pronghorns, tule elk, mule deer, as well wild horses and cattle. The grazers were preyed upon by wolves and mountain lions, and grizzly bears were common, too, because waterways were full of salmon in season. Though visions of that natural past can be glimpsed here and there—on a recent day hike, I saw coyotes, elk, deer, and a golden eagle—this habitat has changed due to the irrigation. Not only was Tulare Lake lost, but one of the West's great salmon streams, the San Joaquin River, was sacrificed for irrigation as well. Only recently, thanks to local activists, have the courts ordered that enough water be released to maintain year-round flow in the stream. And the Valley continues to transform: Some of the older farms that replaced wildlife habitats are themselves being lost to urban and suburban development, at the rate of more than 10,000 acres a year.