By Liam Tiernan
A yearling bull introduced into Minneopa State Park’s wild bison herd has begun assimilating into the herd, and park officials hope the animal will help perpetuate the herd once he reaches sexual maturity.
Bison herds are made up of cows, calves and yearlings, said Minneopa area naturalist Scott Kudelka. Bulls are generally solitary unless they have a harem of females to guard.
The Minneopa herd’s lead female initially tried to drive the yearling away, and the yearling has also been sparring with another young bull in the herd who will eventually be removed. According to Kudelka, these are good signs for the bull.
“These are all normal behaviors for the animals and we’re seeing the yearling fit in really well,” Kudelka said.
The present-day plains bison population is descended from fewer than 100 original animals, According to the American Genetic Association’s Journal of Heredity. Many conservation herds are hybrid bison, bred with cattle in the 19th and 20th centuries to bolster the numbers of the animals and prevent inbreeding in the small herds.
“At one time there were 30-60 million wild bison in North America,” Kudelka said. “By 1889 there were 440 wild bison left, in private herds and parks like Yellowstone.”
“Our herd at Minneopa tested out to 99.8 percent wild bison,” said Kudelka. “That told us we wanted to be a part of that wild bison heritage.”
Kudelka said that Minneopa State Park could grow its herd to 30 or 40 animals comfortably.
In September 2015, the Minnesota Department of Natural Resources introduced three zoo bison and eight bison from Blue Mounds State Park into Minneopa State Park. Three of these animals were pregnant, and the herd’s number with the addition of the yearling is up to 15 animals.
“Our bison are mostly descended from the Wing Cave bison herd,” said Kudelka, referring to one of the herds that survived through the extirpation of the species. “We’re trying to bring in animals from other herds. We don’t want inbreeding.”
The Minneopa State Park bison herd joins a very exclusive club. According to the American Genetic Association, only 4 percent of bison live in herds dedicated to maintaining the natural genetics of the animal. That’s 20,000 animals out of a population of 500,000. Only one of these herds exists with over 1,000 animals that have no known ancestry of cattle.