Play gets a little more serious when calves grow into bulls. These two bulls were much more aggressive than the little calves I had watched at play, but it’s all relative — the old bull laying in the wallow in front of them paid them no heed. They’re all kids to him I suppose.

When you first enter the parks, rangers hand out flyers warning you to steer clear of bison, as they can turn from passive to aggressive rather quickly. I used to think that no one would really need to be told to steer clear of something this large and this horned, but sadly this is not the case. There was a small group of us watching the herd and one of the men got down into the river bed and walked right up to a calf to photograph it. He came back up onto the bank when his wife suggested it wasn’t a good idea to get between the calf and its mother. Fortunately for him it was just cows and calves in the river bed at that point, the herd got a little more testy when the bulls crossed over.

Bison calves frequently play together in ways that mimic the ways of adults, such as head-butting or one climbing onto the other. Not only was the calf on the left not as into playing as the one on the right, but it was substantially smaller to boot. Not to worry, they were playing under the watchful eye of one of the cows.

An attempt to combine the tight portraits of the face from the previous pictures, but also show the varying shades of brown in this bull’s fur. It’s a touch too tight in my opinion but not only did I not have time to take the teleconverter off the big lens, but it was extremely dusty and not the best place to be exposing the innards of the camera.

This is why I think the built-in teleconverter in Canon’s announced 200-400mm lens is so brilliant. Oh what a joy it would be if my 500mm had one! It would solve one of the biggest and most frustrating challenges I face, regardless of whether I’m in the Tetons or Ridgefield.