Why Did the Bison Cross the River?

Bison mothers and children taking part in morning water aerobics.

Your humble blogger snapped this shot while standing between the hungry herd and the good grass up the hill.

Your typical Yellowstone "wildlife" jam.

We aren't exactly sure, but as we were driving one morning in Yellowstone, we noticed a rather large herd of female bison and several calfs running toward the Yellowstone River. The river at this point was at near-record flow and about 50 degrees. The lead bison stopped at the water's edge, as if testing the water, then jumped in and proceeded to swim the 100 or so yards to the other side (where we were standing). Once they hit the shore, they shook
  themselves off like your average dog and took off running up the bank, across the road, and over the hill toward Mary Mountain. This first group was followed by another, then another, and finally a fourth group, all crossing the river and bounding up the other side. Word must have gotten out that morning that the good grass was on the other side of the river.