Rocky Mountain National Park, Colorado

In the summer, before the fall rut, elk migrate to high elevations to graze on fresh grass. Bulls will often graze next to each other, as in this shot - a scene which would not be seen later in the year. I was driving on Trail Ridge Road in the heart of Rocky Mountain National Park when I came across this pair just off the road. I was able to set up and photograph them from about 100 feet away. Amazingly, they were oblivious to my presence. A ranger told me that the bull on the left was believed to have sired 40% of the calves from that area the prior spring.