Yellowstone is home to the grey (or gray) wolf, a large dog-sized canine with a large head, long legs, and, in the winter, bushy gray fur (although the color can vary from white to brown). They have been compared to a German Shepherd in size and appearance.
The gray wolf is a pack animal that lives with a close-knit crew of 4-7 wolves. In Yellowstone there are several well-known packs including the Lamar Canyon Pack and the Druid Peak Pack named after the portion of the park they inhabit. All together there are approximately 75 different packs in the greater Yellowstone region.
Wolves are scavengers and primarily feast on ungulates, large-hoofed mammals, such as deer and elk in the park.
The wolves of Yellowstone have an interesting history. By the end of the 1920s almost all of the United States’ wolves were killed off, predominantly by ranchers protecting their livestock. With the population decimated, Yellowstone National Park began a reintroduction of the grey wolf in 1995. It is one of the few protected havens for wolves in the U.S.
As of December 2014, the park’s wolf population was at 104 wolves in 11 packs. While wolves are protected within the park’s boundaries, outside the park different states have varying laws regarding wolf management. The availability of food within the park also leads to fluctuation in the wolves’ population. Wild wolves have a lifespan of 7-8 years.