There are two species of canines that live in Yellowstone, one is the gray wolf and the other is the coyote.
I was lucky enough to observe two of the wolves during my stay in Yellowstone. The photographs of their to prove that I saw them, but they are poor in quality, because of the distance between where I was and the wolves. The first picture was taken from inside the van, when we came across a crowd of people, and I use my binoculars to sight out the wolf. Initially, the wolf was just laying down, but before we could get out of the van and set up to photograph it, it started moving toward the woods and so all I got was a quick picture of it. The other realtor with the wolves, was sort of in the same way, we came across groups of people looking across to the hillside that was far away, we were able to get out and join them, again, however, the photographs were only enough to show that it was a wolf.
In Yellowstone, at the end of 2011, there were 10 packs of wolves encompassing approximately at least 98 wolves. The wolves feed on elk, bison, deer and other animals. The wolves are usually seen early in the morning or late in the day and some of the best encounters occur during the winter months. Even though I did not obtain decent photographs of the wolves. It still was a pleasure seeing them in the wild.
We saw numerous coyotes, they were usually single, and were out hunting. The Yellowstone coyotes are among the largest coyotes in the United States, averaging in weight between 30 to 40 pounds. As opposed to the wolves, which are wary of humans, the coyotes are less wary, and we were able to get out of the van and set up to photograph the coyotes.
While we were photographing the bison, we found one which had died, and should become a meal for either the wolves, coyotes, or even grizzly bears.
Remember, all these animals are wild and should not be approached. Park rules say hundred yards from wolves or bears and 25 yards from all the other creatures.