CASPER (WNE) — The Eastern Shoshone Tribe has signed an international treaty to increase cooperation among tribes as they work to reestablish buffalo herds in North America.

Tribal representatives from the Wind River Reservation joined the Oglala Lakota Tribe and Alberta’s Frog Lake First Nation in Montana to sign the International Buffalo Treaty last week. The three tribes joined about 30 other Indigenous nations that already signed the agreement.

The first cross-border tribal treaty in about 150 years, it serves as a guide for tribes that want to take, or already have taken, steps to reestablish a relationship with buffalo. Essentially, it acts as an information-sharing tool to pass on best practices when reintroducing the culturally significant animal, said Eastern Shoshone Business Council Co-Chairman Leslie Shakespeare.

“It’s a treaty of cooperation, renewal,” he said. “[Buffalo are] a part of our culture and our health and well-being.”

Used to make shelter, tools, as food and in ceremonies, buffalo are important spiritually and culturally to the Eastern Shoshone and other tribes.

On the Wind River Reservation, 33 genetically-pure Yellowstone buffalo roam about 300 acres. They were first reintroduced in 2016 after more than 130 years away. Leaders of the Eastern Shoshone’s buffalo program hope to have 1,000 bison living on the more than 700,000 acres of suitable land on the reservation.