A herd of purebred bison have arrived at the Bronx Zoo as a gift from a pair of Native American tribes.

The zoo received eight bison — seven females and one male — from the Fort Peck Assiniboine and Sioux tribes in November, marking the first time in history that a tribe has given bison to a zoo, the Wildlife Conservation Society said.

The animals are from the Yellowstone National Park bloodline, which is one of the few genetically pure herds remaining. The majority of bison now have a small amount of domestic cattle genes from past interbreeding efforts to produce a hardier cattle breed, according to the Bronx Zoo.

Leaders from the Fort Peck Assiniboine and Sioux tribes visited the zoo in November and blessed the bison during a sacred pipe ceremony meant to celebrate the relationship between the tribes and the Wildlife Conservation Society, which operates the Bronx Zoo.

The zoo has been working to breed new herds of genetically pure bison for roughly five years, and the gift represents a continuation of that effort.

“The Bronx Zoo played an important historical role in the recovery of the American bison," WCS Vice President Dr. Pat Thomas said in a statement. "By establishing a pure herd here, the zoo will be, in essence, returning to its roots.”