It’s expected that Native American tribes from both the United States and Canada will sign a treaty on Friday. The treaty says that grizzly bears should be protected in and around Yellowstone National Park.

In the last 150 years, only three cross-border treaties have been signed by American Indians, and this one is the first in that time, tribal members say. Yellowstone-area grizzlies have come back from the brink of extinction, the U.S. Fish and Wildlife Service said this year. It wants to remove Endangered Species Act protections from a group of about 700 bears.

Wyoming, Montana, and Idaho would be able to hunt bears that roam outside of the park’s borders if the park changed its rules. On Friday, it’s expected to be signed by the Piikani Nation and other tribes in Alberta, Canada. It says that more than 50 tribes support protecting grizzlies from random killing and preserving their habitat. People from other tribes, mostly in and around the U.S. Rocky Mountain West, are expected to sign the same treaty at a ceremony in Wyoming two days later.

To show their support for other tribes in the United States, the Canada-based tribes have signed the measure. They all have cultural and religious connections to grizzlies; sign it. They say that grizzlies are too sacred and important to be killed by hunters. People from tribes like the Blackfeet Nation in Montana and the Shoshone-Bannock of eastern Idaho say that. If you delist the grizzly bear, you’ll do “irreparable harm” to the places where the bears used to live, Grier said. This will also hurt tribal sovereignty and religious freedom, he said.

A group of tribal members also says the U.S. government didn’t do a good job consulting with them before making decisions about delisting grizzlies. About 50 tribes have been asked about Yellowstone grizzlies by the U.S. Fish and Wildlife Service since 2014. They’ve been sent letters, phone calls, and emails. Thursday, she said: “The service has and is still meeting with Indian tribes west of the Mississippi.”