The Assiniboine Park Zoo is investigating how one of its animals got out of its enclosure.

It happened on May 26, when a 200 lb. male muskox escaped its area, but didn't get out of the secondary containment area.

"What we do know is that after the fact, the gate was partially open and we have not been able to identify mechanical failure at this point,” said Gary Lunsford, Assiniboine Park Zoo’s Senior Director of Animal Care and Conservation.

The zoo said staff sedated and relocated the animal quickly.

This isn't the first time an animal at the zoo has ended up somewhere it wasn't supposed to be.

In 2014, just days after the Journey to Churchill exhibit opened, some grey wolves tunneled into the polar bear pen.

No animals were hurt and the wolves were moved out of the exhibit before any visitors arrived.

"We initiated an emergency response, and the emergency response team was on site within minutes and sedated the animal directly after," said Lunsford.

Zoo officials said the muskox broke one of its horns off while it was recovering from sedation. It said the animal is doing well under veterinary care.

The group that accredits the Assiniboine Park Zoo said it is aware of the incident with the muskox.

Canada's Accredited Zoos and Aquariums sent this statement to CTV News:

“CAZA’s Executive Director was made aware of the incident last Friday. We understand that the matter was resolved quickly without endangering the safety and security of the staff, visitors, or animals in the care of Assiniboine Park Zoo. As per CAZA’s standards on emergency protocol, the Assiniboine Park Zoo will be submitting formal documentation to CAZA’s National Office outlining the details of the matter and what steps are being taken to ensure the incident is not repeated. It is a testament to the Zoo’s dedicated staff and emergency protocols which abled the facility to respond to the situation quickly without harm.”