Zoo Knoxville is adding some sparkle to a tiger's diet -- literally.

Arya is a 5-year-old Malayan tiger, and Zoo Knoxville is hoping that she can soon be a mom.

She came to Zoo Knoxville in 2017 from a zoo in Fresno, CA, and it's been recommended she breed with one of the male tigers, Bashir, in Knoxville.

"She just had her first full estro-cycle in December of last year, and so the next step is we're watching her behavior very closely," said Petty Grieve, the Asian Trek and Grasslands Africa Curator at Zoo Knoxville.

That's hard work. It includes watching hours of footage of Arya's behavior.

"She's spending restless time overnight, where she's checking the howdy doors, she's looking for the boys, seeing what they're doing," Grieve said. "But then she'll also go and plop down on her back and roll around and show her belly."

Grieve says this behavior could mean Arya is ready to mate.

But to be really, really, scientifically sure-- that's where the glitter comes in.

"We actually put glitter in her meat every day and that way it comes out on the other side," Grieve said.

Because-- Zoo Knoxville has three tigers, and they want to make sure they have the right number two.

That waste gets sent to a lab in St. Louis where they can test for hormones.

You may laugh, but Arya's glitter is part of a really important process.

"The Malayan Tiger is critically endangered," Grieve said. " There's probably new research coming in now, but there's probably fewer than 400 left in the wild, and there's 60 in U.S. zoos."

Grieve says they will wait for Arya to cycle a few more times before they introduce her to her mate, Bashir. When they do, they will take a lot of precautions.

"When we set up we'll have CO2 fire extinguishers, we'll have hoses, air horns, keepers will be monitoring introductions on cameras, we'll do it off exhibit, so we have lots of ways to separate them should it go bad," Grieve said.

But, Grieve says Arya and Bashir have known each other for two years and already have shown some chemistry.

Read more at WBIR's website.