For years, meals at the summer sun dance ceremonies on the Eastern Shoshone tribe’s lands in Wyoming were missing something that was once a staple of the sacred rituals.

There was no presence of homegrown bison, an animal central to the spiritual customs and beliefs of the Shoshone and other Native Americans.

Now, meals at the annual ceremonies, which have just begun for this summer, will feature bison meat that, for the first time in 138 years, was harvested from the tribe’s own lands. The multiday sacred ritual involves dancing, fasting and praying, often within a sweat lodge made from natural materials.

“It’s in our DNA to have that animal around us again,” said Jason Baldes, 44, a member of the Eastern Shoshone tribe who manages its herd of bison on the Wind River Indian Reservation in Wyoming. “It’s kind of like bringing home your long-lost relative.”

Indigenous tribes across the United States and Canada have been rebuilding their bison herds for decades, thanks partly to transfers from government agencies and nonprofits, and have made rapid progress in the past few years.

The bison brings conservation benefits to the complex grassland ecosystems where the animals once played a crucial ecological role.

And on tribal lands, their restoration is part of a reckoning with a dark history: Bison were once nearly eliminated from the continent as part of campaigns to repress Indigenous tribes that relied on the animals for food, shelter and spiritual practices, including the sun dance.

In the United States, “it was congressionally encouraged to eliminate the buffalo to subjugate Native Americans to reservations, starve us into submission and then take our land,” Mr. Baldes said, using the term for the animal that he prefers.

“That’s really what happened,” he added, “so the restoration of buffalo back to our tribes and communities and reservations is part of our healing.”

Before European colonization, North America had an estimated 30 to 60 million plains bison, one of two subspecies of the American bison. They once supported a huge range of other species, including migratory birds that feed off the insects that thrive in bison dung.

But a mass bison slaughter began in the late 1700s and moved west across the United States and into Canada, according to “The Ecological Buffalo,” a recent book by Wes Olson, a former warden in the Canadian national park system. By the late 1880s, there were only about 281 plains bison left, including 23 in Yellowstone National Park, which is mostly in Wyoming.

Colossal herds of bison won’t roam North America again anytime soon. Today only about 420,000 remain in commercial herds, and another 20,000 or so are in so-called conservation herds that have never bred with cattle, unlike commercial herds, according to United States government data. The conservation herd numbers have not budged since 1935, and the U.S. Interior Department says that bison are functionally extinct on grasslands and within the “human cultures with which they co-evolved.”

But Mr. Olson said the pace of conservation bison transfers to Native American tribes has picked up over the past five or so years in Canada and the United States, aided in part by a 2014 cross-border buffalo treaty among some tribes, which has since grown to include others.

In one sign of momentum, the InterTribal Buffalo Council, a consortium of 80 tribes across 20 U.S. states, transferred about 5,000 bison over the past five years, including more than 2,000 bison last year, according to Mr. Baldes.

Building up the continent’s conservation bison herd is “something that should be applauded,” said Daniel Kinka, the wildlife restoration manager at American Prairie, a nonprofit in Montana that is working to restore prairies where the animals can thrive. “And much of the credit goes to Indigenous people that are leading the way.”

In the United States, tribes have been receiving conservation bison from government agencies, nonprofits and other tribes. Mr. Baldes said a bison conservation order in March from Interior Secretary Deb Haaland, which included $25 million to help with tribal bison restoration, would help further such efforts.

In some cases, bison meat harvested from Native American lands is being sold or donated, as it was during the coronavirus pandemic on the Wind River Reservation in Wyoming.

For the Texas Tribal Buffalo Project, live bison are part of a program that teaches Indigenous youth about the animal, said the organization’s founder, Lucille Contreras of the Lipan Apache tribe.

Ms. Contreras, 56, said that she started the nonprofit partly as a way to address the persecution of her tribe in the 1800s, and as a vehicle for tribes to reconnect with one another.

“We have needed this healing in Texas for so many years,” said Ms. Contreras, who also manages 15 donated conservation bison on 77 acres in her tribe’s homeland.

In Oklahoma, the Yuchi tribe is rebuilding its bison herd from scratch, starting this year, thanks to a recent donation from the city of Denver. The hope is that the animals will help to reestablish cultural and spiritual bonds between the animal and the tribe that were broken in the 1830s, when the Yuchi people were forcibly relocated to present-day Oklahoma from the Southeastern United States, said Richard Grounds, a member of the tribe.

Mr. Grounds said the Yuchi identify with the plight of the bison in part because they, too, were targeted for extinction and survived.

“Our people were kicked out, but we brought our ceremonial fires with us,” he said. “We have been singing the buffalo dance song every summer solstice for the last 200 years.”

Sun dances were banned by the United States government in the 19th Century, forcing some tribes across the Great Plains to either abandon the ritual or practice it in secret. But the government began reversing its policies in the 1930s, and a 1978 federal law guaranteed tribes the right to practice religious rites and ceremonies.

Now, the restoration of tribal bison is reinvigorating the ritual. Mr. Baldes said the Eastern Shoshone’s three sun dances on the Wind River Reservation this summer will feature locally harvested bison for the first time since 1885 — an important development for a people known by other bands of Shoshone as the “buffalo eaters.”

For the Eastern Shoshone, the ritual is rooted in a legend in which a member of the tribe had a vision of bison, said James L. Trosper, 61, who runs one of the summer’s three sun dances. The sweat lodge where the healing ritual occurs also features a bison head hanging from its roughly 50-foot-tall cottonwood center pole, which the tribe believes is a conduit for their creator’s spiritual power.

Mr. Trosper, whose great-grandfather taught him how to run the sun dance, said that when the current bison head is retired, the Eastern Shoshone people plan to replace it with one from their own lands.

“If it were made out of a buffalo from here, it would just mean so much more to us,” he said. “To me, the power and the medicine would be stronger.”