The Yellowstone River valley provided abundant wildlife for the Corps of Discovery after periods of near starvation earlier in the journey. Wildlife supplied the Corps with more than meat: buffalo, deer, and elk hides replaced threadbare clothing, buffalo hides were made into moccasins for sore-footed horses, and bear grease was used as protection against mosquitoes. William Clark recorded chasing a white or gray bear on horseback for about 2 miles on July 16, 1806, seeing immense herds of elk feeding, noting more deer and fewer elk on July 17, 1806, using part of the skin of a very fat buffalo bull on July 16, 1805, to make moccasins for some lame horses, observing that buffalo had become much more plentiful by July 17, 1806, and seeing about 200 elk and nearly as many antelope on July 16, 1806.