How Many Wolves Are in Yellowstone National Park?

Yellowstone National Park is the best place in the world to see wolves in their natural habitat. But just how many wolves roam the park today? The current population (in December of 2024) of wolves in Yellowstone is estimated to be around 120 individuals, distributed among 9 packs. This number can vary year to year due to natural factors like prey availability, pack dynamics, disease, and human interactions outside park boundaries. On average, there are 100 to 110 wolves distributed in 8 to 10 packs. 

Wolves breed in February and pups are born at the end of April or beginning of May. Pups take time to grow, learn and mature so the wolf pack, which is like an extended family, maintains a territory from spring until autumn. In the winter months, pups will join the rest of the pack, spreading out from their pack’s territory to follow prey animals (elk and bison) as they migrate to winter range. Winter is a very challenging time for elk and bison. Many of them do not survive the winter because of extreme cold and low quality food. As a result, wolves tend to have more vulnerable prey, and thus more food available to them in the winter. Even so, some wolves don’t make it through the winter and the population is usually lowest in April.

A Brief History of Wolves in Yellowstone

The story of wolves in Yellowstone is one of both loss and restoration. Wolves were eradicated from the park by the mid-20th century, with the last known Yellowstone wolf killed in 1926. Their removal caused profound ecological imbalances, particularly affecting elk populations, which grew unchecked and altered the park’s vegetation and ecology. Although wolves occasionally passed through in the 1930s and one was seen in 1994, lobos were functionally absent in Yellowstone for 70 years.

In 1995 and 1996, as part of a groundbreaking restoration project, 31 gray wolves were reintroduced to Yellowstone from Alberta and British Columbia, Canada. This marked the beginning of one of the most successful conservation stories in history. The wolves adapted quickly to their new home, forming packs, establishing territories, and hunting prey such as elk, deer, and bison.

Population Trends Over the Years

Following their reintroduction, the wolf population grew rapidly, peaking at 174 wolves in 2003. Since then, numbers have stabilized at lower levels. This stabilization is influenced by various factors, including:

1. Prey Availability: Wolves primarily prey on vulnerable young, old or sick elk, which have decreased in number due to both wolf predation and environmental changes.
2. Territorial Disputes: Packs compete for space and resources within the park, which naturally limits population growth. Conflict with other wolves is the most common cause of death in Yellowstone’s wolves.
3. Disease: Diseases like distemper and mange occasionally impact wolf numbers. A 2022 study showed that toxoplasmosis appears to alter wolf behavior in some interesting ways.
4. Human Interaction: While wolves are protected within Yellowstone, those that roam outside the park’s boundaries face threats like hunting, trapping and snaring. The number of wolves killed beyond the boundaries depends on state laws, hunting regulations and quotas in the adjacent states of Montana, Wyoming and Idaho. In the winter of 2021-2022, over 20% of Yellowstone’s wolf population was killed by humans. This eliminated some packs, others lost their breeding female and had no pups for that year, while some mostly intact packs had compensatory breeding.

Why Do Wolf Numbers Matter?

The number of wolves in Yellowstone has significant ecological implications. Wolves are apex predators and play a vital role in maintaining the balance of the ecosystem. Their presence helps regulate prey populations, which in turn influences vegetation growth, stream health, and habitat conditions for other species. For example, the reduction in elk numbers and changes in elk distribution following the wolves’ reintroduction, combined with recovery of Yellowstone’s grizzly bear and mountain lion populations, has allowed willow and aspen trees to recover in some areas, potentially benefiting species like beavers and birds. 

Are Wolves Killing Too Many Elk?

Compared to other predators, wolves often fail. Their success rate for killing elk is between 5 and 20% depending on how experienced the wolves are who are chasing the elk. Success rates for wolves hunting bison are similar in late winter when bison are weakened, but can be much lower throughout the rest of the year. Wolves are often injured by elk kicking them or bison goring, tossing or trampling them. As part of the Yellowstone Wolf Project, field biologists in Yellowstone have been studying what wolves eat for many years. They hike or ski out to carcass sights to learn what they can about the animals wolves kill. The have documented that wolves remove the most vulnerable prey: mostly young, old, sick and injured elk and bison, sometimes deer and rarely moose, bighorn sheep and mountain goats. A balance persists because wolf abundance depends on the availability of vulnerable prey, not just any elk or bison will do. 

Observing Wolves in Yellowstone

For visitors hoping to catch a glimpse of these iconic animals, Yellowstone’s northern range—particularly the Lamar Valley—offers some of the best wolf-watching opportunities in the world. Professional guides can help visitors in spotting wolves, especially during dawn or dusk when the animals are most active. Spotting scopes help you see wolves up close without being in close enough proximity to alter their behavior. This is key to good wildlife observation and keeping wolves safe.

Looking Ahead

Yellowstone’s wolf population will likely continue to fluctuate within a stable range, influenced by ecological factors and ongoing conservation efforts. The Yellowstone Wolf Project, a dedicated research initiative, monitors the packs closely and provides valuable insights into their behavior, population dynamics, and impact on the ecosystem.

For those interested in learning more, the park publishes an annual Wolf Project Report, which details the latest population data and research findings. Yellowstone’s wolves are not just a symbol of wildness but also a testament to the power of conservation and the resilience of nature.

Whether you’re a wildlife enthusiast, a conservation advocate, or simply a curious traveler, the wolves of Yellowstone offer a compelling glimpse into the intricate web of life that defines this iconic national park. Come join one of our local biologist-guides on a private trip to watch wolves in Yellowstone and see for yourself. Click here for more information.