Lassen Pack

The Lassen Pack is a gray wolf (Canis lupus) pack inhabiting Lassen National Forest and adjacent lands in Lassen County and Plumas County in Northern California. Confirmed by the California Department of Fish and Wildlife (CDFW) in fall 2016, it was the first self-sustaining wolf pack documented in California since gray wolves were extirpated from the state in the early 20th century.¹

The pack's founding male, CA-08M, was a son of OR-7, the first wolf confirmed in California since the 1920s. The founding female, LAS01F, was not related to any known Oregon wolf and is believed to have dispersed independently from the northern Rocky Mountain wolf population, traveling an estimated 800 miles (1,300 km) or more through the Great Basin Desert.²

The pack produced documented litters annually through 2022 and became the most closely monitored wolf pack in California. Offspring from the Lassen Pack contributed to the founding of at least two subsequent California packs — the Beckwourth Pack and the Yowlumni Pack.

OR-7, a male wolf from Oregon's Rogue Pack, entered California in December 2011 and became the first wolf confirmed in the state in nearly a century.³ He eventually returned to Oregon and formed the Rogue Pack, which produced CA-08M, the wolf who would become the Lassen Pack's founding breeding male.⁴

The founding female, LAS01F, was born in 2014, possibly in Wyoming, where she has known half-siblings. Genetic analysis established that she was not related to any Oregon wolf population; she likely dispersed from a segment of the northern Rocky Mountain population and traveled through the Great Basin Desert of Utah and Nevada, or alternatively through Idaho and Oregon, before reaching California.² CDFW biologists confirmed two wolves in Lassen County in fall 2016, establishing the Lassen Pack as the first resident pack in California in the modern era.⁵

In June 2017, CDFW biologists fitted LAS01F with a GPS tracking collar, making her the first breeding female wolf collared in California.⁵ Genetic testing traced the four pups born that spring to CA-08M, son of OR-7, making OR-7 a grandfather through this pack.¹

CA-08M and LAS01F produced five pups in 2018⁶ and four pups in 2019.⁷ CA-08M was last detected with the pack in spring 2019. A black-colored adult male, designated LAS16M, joined the pack as early as June 2019 and became the new breeding male.⁸

In 2020, the pack produced two litters totaling eight pups. LAS09F, a two-year-old female, gave birth to one of the litters alongside LAS01F.⁹ In October 2020, a collared young male from the pack, LAS13M, traveled north to Lake County, Oregon, demonstrating the dispersal capacity of California-born wolves.¹⁰

LAS01F was not detected after fall 2020. In 2021, LAS09F became the pack's primary breeding female, producing six pups.¹¹ The Lassen Pack's 2021 litter, alongside the Whaleback Pack's concurrent litter, marked the first time in over a century that two California wolf packs had produced pups in the same year.⁹ The pack produced five pups in 2022.¹²

The Dixie Fire, which began in July 2021 and burned approximately 963,000 acres across Plumas, Lassen, Shasta, Butte, and Tehama counties, swept through the Lassen Pack's core home range. CDFW confirmed the pack had survived when biologists detected pack members within the burn perimeter during the fire.¹³ The fire destroyed significant portions of the forest within the pack's established territory.

CDFW GPS telemetry data placed most of the Lassen Pack's activity in western Lassen County and the northernmost portion of Plumas County.⁸ The pack's home range encompasses portions of Lassen National Forest, where the U.S. Forest Service documented the pack via trail camera beginning in 2017.

LAS12F, a female from the Lassen Pack's 2019 litter, was identified as one of the founding wolves of the Beckwourth Pack, confirmed in eastern Plumas County in May 2021.¹⁴

The Yowlumni Pack, confirmed in Tulare County in August 2023, approximately 200 miles (320 km) south of the Lassen Pack's territory, included a breeding male descended from the Lassen Pack.¹⁵ The adult female of the Yowlumni Pack is a direct descendant of OR-7, making her a descendant of the Lassen Pack's founding lineage on both sides.