This zoo "baby" is now coming in at over 500 pounds in size! 

The Denver Zoo announced some big news last week when it comes to their baby rhino! The not-so-little Joona, who is just over 4 months old, has outgrown her former yard, and is now out in a variety of habitats for her adoring fans to see! 

"Our little Joona has been growing leaps and bounds, so much so that she’s moved beyond her formerly baby-proofed yard! These days, you could catch her in a number of habitats as she’s recently hit 536 lbs and has been confidently swimming in the shallower areas of our pools," said the zoo. 

Check her exploring and stretching her adorable legs in the big yard at the zoo! Not to mention trying to get mom's attention whenever she can. 

Joona joined the zoo family in late February, and she is the first calf of 13-year-old Tensing. It took several tries for Tensing to conceive via artificial insemination, and her pregnancy lasted about 15 months long! She is the first-ever greater one-horned rhino born at the Denver Zoo. 

"The birth of this calf is the result of a truly heroic effort by our animal care, health and science teams and partners from other zoos to support the species,” said Brian Aucone, Senior Vice President for Animal Sciences upon Joona's birth. “It’s a significant event for several reasons, including the fact that this is the first greater one-horned rhino born at Denver Zoo, and because it was another very important step in reproductive science for animals in the wild and human care.”

Joona's name was chosen by zoo fans, and it means "treasure" or "joyful in nature" in Nepalese. 

And while she currently weighs 536(!) pounds, the zoo says she's still a bundle of youthful energy and will be for quite a while.

"She’s still rambunctious as ever and has a long ways to go before she’s full grown, alternating between naps and zoomies most days," the zoo said. 

Have you seen Joona out and about! Let us know in the comments!