Yellowstone Wolf Project

Yellowstone Wolf Project

Why this work matters

The nationally acclaimed Yellowstone Wolf Project oversees all research and monitoring efforts regarding wolves in Yellowstone. It is the only continuous program in the region, and it maintains a 25-year period of wolf study and analysis. Year-round field research helps biologists gain data that will inform wolf management decisions for years to come as well as contributing to a greater understanding of Yellowstone’s ecosystem.

What needs to be done

In order to effectively understand our wolf population, continuous year-round research is needed. We are able to capture necessary data through the following research methods:

  • GPS collaring
  • Radio telemetry tracking
  • Aerial monitoring flights
  • Genetic testing and lab analysis
  • Predation studies
  • Population counts and pup survival counts

The Yellowstone Wolf Project relies on the funding from Yellowstone Forever’s members and corporate partners to continue this crucial research on Yellowstone’s wolves.

A Wolf Project member conducts a research flight in Lamar Valley.

What we’ve accomplished

The wolf, one of Yellowstone’s most important predators, roamed its landscape and defined its ecosystem for thousands of years. By the 1920s, the last wolf pack in Yellowstone was killed in an effort by the U.S. government to tame the wilderness. This action had a profound effect on Yellowstone. Elk and coyote populations boomed. Beavers became increasingly rare, and so did willow and aspen trees. The park was missing a keystone species and it affected the balance of the entire ecosystem.

Starting with the watershed Endangered Species Act in the 1970s, and finally in 1995 with all the pieces in place, fourteen gray wolves were captured in Canada and relocated to Yellowstone’s Lamar Valley. In 1996, 17 more Canadian wolves were brought into the park, followed by 10 wolves from northwestern Montana in 1997. The wolf population grew quickly, as pack territories and breeding pairs were established.

This monumental undertaking marked the first deliberate attempt to return a top-level carnivore to a large ecosystem. Its impact has been significant; wolves have affected the dynamics of the entire Yellowstone ecosystem.

Every year since the Yellowstone Wolf project reintroduced wolves to Yellowstone in 1995, Yellowstone Forever has provided 60% of the project’s yearly budget through private funds.

Wolf Project Highlights

1995-1996: After 20 years of planning and study, wolves were reintroduced into the greater Yellowstone ecosystem. Wolves unexpectedly bred in their acclimation pens, producing two litters. By the end of 1996 there were 51 wolves in nine packs.

1997-1998: The Yellowstone Wolf Project began to systematically capture wolves for research and monitoring purposes. Twenty-seven wolves were captured this year, either by helicopter netting or darting. At the end of 1998, about 112 wolves in 11 packs inhabited the Yellowstone ecosystem. In March 1998, Doug Smith took on the role of full-time project leader.

1999-2000: For the third year, wolf captures were conducted to put on radio collars and collect measurements and samples. Of at least 177 wolves in the ecosystem at the end of 2000, 43 (24%) were collared.

2001-2002: At the end of 2001, at least 218 wolves were present in the Greater Yellowstone Ecosystem in 25 packs. The largest of those packs, the Druid Pack at 37, but that pack dispersed and reduced in 2002. A new pack was formed in the Bechler region, the first recorded activity of a pack there since wolf reintroduction.

2003-2004: The Yellowstone Wolf Project recorded its best radio-collaring year in 2003 with 38 wolves captured and handled. At year end, all but one pack in the park was collared. As of the end of 2004, all 31 of the originally reintroduced wolves were dead. All wolves currently alive are descendants.

2005-2006: At the end of 2005, at least 118 wolves in 13 packs occupied the park. This represents a decline of 51 wolves, the largest population decline since reintroduction. The decline is largely attributed to poor pup survival. Wolf population increased again in 2006, with 136 wolves in 13 packs. A new type of radio collar was deployed in 2006. The ARGOS collar is designed to track animals in remote locations that are hard to track via fixed-wing aircraft. These collars use satellite technology that can forward data to the wolf office via email.

2007-2008: 2007 was the first year since the reintroduction that no new packs formed. T2008 saw another decline in overall population, down 27% to 124 wolves in 12 packs. Multiple packs dissolved or dispersed, and the status of a few others was in question.

2009-2010: Population numbers declined again, to 96 wolves in 14 packs. Intraspecific strife, food stress, and mange were the likely causes of the decline. For the first time a wolf was intentionally killed in the park because it had become food conditioned and threatened human safety.

2011-2012: By 2012 wolf numbers had declined by about 50% since 2007 mostly because of a smaller elk population, the main food of wolves in the park. At the end of 2012, there were at least 83 wolves in 10 packs.

2013-2014: The wolf population in the park remained steady in 2013. At year’s end, 24% (21 wolves) of the wolf population was collared. In 2014, for the first time since the beginning of the Yellowstone Wolf Project, the size of a wolf pack was estimated via genetic sampling methodology, using scat samples from a den site. Pack size averaged 9 wolves, with a range from 2 to 14.

2015-2016: With the disappearance of the Yellowstone Delta pack in2015, the Mollie’s pack (originally named the Crystal Creek pack) became the longest current intact pack of any in the park at nearly 21 years. In 2016, for the first time in Bechler territory, staff deployed two remote cameras on a game trail during the fall months. Cameras successfully captured images and videos of five adults (one a white wolf) with four pups. Also, for the first time in several years, there were no reported hazing events on habituated wolves.

2017-2018: In 2018 overall population numbers dropped to 80 wolves in 9 packs living primarily in the park. The project’s exceptional record was again leaned on with Doug Smith, leader of the Yellowstone Wolf Project, advising the relocation program for Isle Royale wolves on Isle Royale National Park.

2019: Population numbers rebounded due to high adult survival and several packs producing multiple litters. The overall population was 94 wolves in 8 packs.

From a donor:

To hear a wolf howl with all the answering howls was something I’ll never forget. This is why we continue to give. That’s an experience too few of us have and must be preserved. — Tim S., Connecticut

  • Collecting Samples for DNA