Wolves in Yellowstone




Although wolf packs once roamed from the Arctic tundra to Mexico, loss of habitat and extermination programs led to their demise throughout most of the United States by early in the 1900s. In 1973, the US Fish and Wildlife Service listed the northern Rocky Mountain wolf (Canis lupus) as an endangered species and designated Greater Yellowstone as one of three recovery areas. From 1995 to 1997, 41 wild wolves from Canada and northwest Montana were released in Yellowstone National Park. As expected, wolves from the growing population dispersed to establish territories outside the park where they are less protected from human-caused mortalities. The park helps ensure the species' long-term viability in Greater Yellowstone and has provided a place for research on how wolves may affect many aspects of the ecosystem. Learn More: Wolf Information Continued…


Quick Facts About Wolves in Yellowstone

  • 26–36 inches high at the shoulder; 4–6 feet long from nose to tail tip
  • Males weigh 100–130 pounds; females weigh 80–110 pounds
  • Average lifespan is about 5 years in wild; can live up to 12 years in wild
  • Three color phases: gray, black, and white; gray is the most common; white is usually in the high Arctic; and black is common only in the Rockies
  • 400–450 wolves in the Greater Yellowstone Ecosystem
  • Prey primarily on hoofed animals. In Yellowstone, 90% of their winter diet is elk; more deer in summer; also eat a variety of smaller mammals like beavers
  • Mate in February; give birth to average of five pups in April after a gestation period of 63 days; young emerge from den at 10–14 days; pack remains at the den for 3–10 weeks unless disturbed.

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