Why is Bitter Creek bitter?
Watch the sunlight sparkle on Bitter Creek as it flows in the valley below the caves. It's bitter because it contains minerals that give it an unpleasant taste. Animals don't seem to mind the taste. They drink the water anyway. Sometimes, Bitter Creek becomes much larger and swifter when the snow melts in the mountains in the spring or when it rains very hard.
The intermittent stream below the caves in the valley provides water for wild animals just as it has for thousands of years. The water tastes bitter due to the high levels of natural minerals and alkali, so it is not ideal for humans. At the mouth of Bitter Creek is one of the best Yellowstone River fords. During spring runoff and occasional heavy rains, this peaceful stream can be a raging torrent for short periods of time.
"One very vivid recollection was a cloudburst in about 1914 when Bitter Creek resembled the Yellowstone River. I think all of our hogs were drowned. A field of recently cut hay lodged against a hay rake left in the field and the rake was never found. It probably wound up in the Yellowstone (or maybe the Missouri). Who knows? Nearly all of the young turkeys and chickens were washed out from under their mothers who sought to hover them." Recollection of Kenneth Valentine. Montana Fish Wildlife and Parks, Pictograph Cave State Park Trail Guide, 1997.