Judging from its almost leisurely mid-summer passage as a braided river through the park you would not guess what chaos lies downstream. The river had at least two names before the Snake was affixed. A group of French-speaking trappers who crossed the river in September 1811 encountered such difficulty they decided to give it the name Mad River. Sometime later this trapping party had to cross it again downstream near its confluence with the Hoback River and renamed it _La Maudite Rivière Enragée_—Accursed Mad River. Those names properly hint at what lies downstream as the Snake flows in every direction but east in a great sickle-shaped curve, its watershed embracing the largest chunk of wilderness in the United States outside Alaska. The Snake’s beautiful Shoshone Falls in Idaho is a full 43 feet higher than Niagara Falls. And the Snake’s Hells Canyon, also in Idaho, is North America’s deepest and narrowest major gorge, averaging a deeper gash across the land than the Grand Canyon itself. Hells Canyon plunges 7,900 feet at its deepest point. What is more, it averages 5,500 feet deep over its course. In a valley this high (the elevation of Jackson Hole at the lower end measures 6,000 feet) the Snake should have cut, with its steep gradients, permanent channels. Instead, it still wanders in myriad channels across the glacial debris filling the fault basin. Here the Snake looks more like a prairie river rambling with the restlessness of youth. Its banks are a checkerboard of successional stages, as plant communities rise and fall with disturbances created by flooding, channel shifting, or fire. This benefits the moose and beaver by assuring continual supplies of willow and cottonwood that would otherwise soon be succeeded by blue spruce. The Snake, discovered by Lewis and Clark in 1805 but not fully explored until its headwaters were pinpointed in 1970, is no longer a completely wild river even in the park. Jackson Lake Dam, built before the park was established, controls the water flow below the lake, moderating natural surges that used to follow rapid spring snowmelt or violent summer thunderstorms. Since the river no longer scours the valley regularly, these stabilized conditions favor the development of larger tracts of blue spruce. Compared to the lakes, the Snake harbors a wealth of aquatic life. A river is richer partly because its linear structure provides more shoreline. The plant complex that the river makes possible continually enriches the water with leaves and other debris. This energy subsidy, along with the countless terrestrial insects caught by the river, is passed up the food chain. Eventually the additional energy is translated into the fish that help support the herons, mergansers, eagles, ospreys, otters, and other terrestrial predators that use the aquatic food pyramid.