Cancer claims 'sweetheart' wolf at Winnipeg's Assiniboine Park Zoo

Onyx, a 13-year-old grey wolf at Winnipeg's Assiniboine Park Zoo, has died after a battle with cancer, the zoo says.

Known as a "sweetheart and a gentle wolf" by her care team, Onyx was the only female member of a five-wolf pack at the zoo, which included her four brothers, according to a Thursday post on the zoo's Instagram page.

"Onyx was a tough cookie. She lived with four male wolves and it didn't hold her back in any way," the post stated. "She would muscle her way through them at feeds and was not intimidated at all when they had disagreements."

Her care team also considered her the smartest wolf in the pack, always interested in enrichment activities and in rubbing anything very smelly all over herself, the zoo's post stated.

Onyx, who would have turned 14 in January, died on Nov. 12. She and her four brothers originally came to the Winnipeg zoo in 2014 from a private facility in British Columbia.

WATCH | An Assiniboine Park Zoo video about its wolves:

As a geriatric animal, she was given close monitoring and health checks, which led in 2018 to the discovery of a tumour along her mammary glands, said Dr. Chris Enright, the zoo's director of veterinary services and animal welfare.

Several more masses were found in the following years, and Onyx underwent multiple surgeries and treatments to remove them.

"The good news with each of those individual surgeries is that the masses were benign," Enright said. "Unfortunately, in September, the mass that we removed … came back from the lab as no longer being benign — it was more aggressive."

The malignant tumour ended up spreading throughout her body.

Onyx's four brothers continue to live in their enclosure and are adjusting to the change.

"They haven't shown us all any real disorder in their social behaviour in the past week, but it's something that we will be watching for closely," Enright said, noting Onyx could often serve as a peacemaker in the pack.

"Onyx was an incredibly social animal. All wolves, they want to live in a pack, they're very social animals, but Onyx got along with everyone," he said.

"With some of the other wolves you'd see posturing. You'd see, 'I want this food.' 'No, I want this food.' But Onyx was everyone's buddy."

She enjoyed people and interacting with her environment, which made her a wonderful representative of her species, Enright said.

"Wolves are an animal that people have sort of a bad history with, at times eliminating wolves in the landscape. She was a great ambassador in helping to tell the stories of being able to live alongside wolves," he said.

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"Onyx was absolutely both sweetheart and gentle. Wolves are complex creatures and very social creatures, and they all have their own personalities. Onyx was really a personable wolf."

Onyx isn't the only animal the zoo has had to say goodbye to recently. In June, Aurora, a polar bear who had been at the zoo since 2013, died during a routine dental examination.

"When we have animals in our care, you know, we care deeply for them and we can work with them for many years," said Enright. "It's certainly close to home [when they die]."