River crossing turns perilous for Yellowstone bison calves

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.