The Minnesota Zoo has bid farewell to two musk oxen.
Earlier this month, the zoo released a statement on their website announcing that they humanely euthanized the last two musk oxen at their facility. The zoo made the difficult decision based on the animals' significant health problems and worries that climate change and increasing temperatures within the state could make the musk oxen's final days more challenging.
The zoo's post explained that the two female animals had shown signs of "progressive age-related health issues" and that rising temperatures throughout the past 10 years affected the health of the musk oxen, which typically call the arctic tundra home.
"It seems even Minnesota has now become too far south for this species to thrive," the zoo said.
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"We saw firsthand just how much the seasons and temperature and humidity played a role in how they thrived or not," said zookeeper Cindy Bjork-Groebner. "It was very weather dependent with them."
"You could tell they were thriving when the temperatures were colder and then the minute the heat and humidity hit, that's when I really started watching and could notice changes," she continued.
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Noticing the change in the animals over time, the zoo decided to stop breeding musk oxen and not welcome any new herd members around a decade ago.
"I think the best thing we can do as keepers is try to do the best we can for each animal each and every day," Bjork-Groebner added.
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"It's a long conversation between veterinarians, curators, and zoo leadership," Dr. Yaw, the manager of the zoo's animal health department, said of the decision to humanely euthanize an animal. "We have a responsibility to these animals. When it comes to a point that we can't manage clinical health issues, this is the most humane choice we can make."
"Both of these musk oxen were geriatric animals that had significant health issues. And these were age-related health issues that had progressed over some time," a zoo representative told PEOPLE about the difficult choice to say goodbye to the zoo's last musk oxen. "We recognize that the warming temperatures really exasperated these age-related issues. But the decision to humanely euthanize wasn't due to climate change; it was based on the significant age-related health issues and knowing that these would continue to be exasperated by this year's warm weather."
According to the zoo, a group of Asian wild horses is occupying the former musk oxen habitat for the time being. The facility did not state whether or not they will replace the species with another animal.