Yellowstone National Park abounds with wildlife and visitors typically leave with wonderful memories involving critters they had encountered.
But visitors who spend enough time in the park also witness heart-wrenching scenes that leave them wondering why nature can seem so cruel.
In late May, I pulled over west of Lamar Valley and watched from a distance as a bison herd began to cross the Lamar River.
Momma bison searches for calf downstream.
The river was shallow but with deep, swift-running channels.