"Her little system is underdeveloped, and getting her to a healthy weight will be a challenge. Vets and animal staff are doing everything they can to get her through this critical time."

That's what Christina Gorsuch, curator of mammals at the Cincinnati Zoo, wrote Jan. 24, 2017, following the premature birth of a female hippo. The survival of this tiny creature, weighing a mere 29 pounds (hippos normally weigh around 55-120 pounds at birth), was definitely not a sure thing.

Almost a year later, that same hippo weighs more than 650 pounds and is known the world over by just a single name: Fiona.

The little hippo that could

Right after Fiona was born, zookeepers nursed Fiona's mother, Bibi, for milk and bottle fed her baby. The zoo had to contact nearby Children's Hospital when Fiona stopped eating and had to be connected to special IVs. They cuddled with Fiona to give her body heat; one of Fiona's first nicknames was actually Little Spoon.

Slowly and steadily, Fiona began to thrive. She took her first steps Feb. 5 and, two days later, took her first dip in a tub of water so she could learn how to dive, swim and surface. By April, Fiona weighed almost 150 pounds and was allowed to begin practicing her sweet swimming moves in the indoor grown-up hippo pool. From there on out, it was smooth sailing.

Fiona's story of perseverance caught the attention of people all over the world. They sent in cards, drawings and money to support Fiona (and the zoo) as her keepers worked to get her to developmental milestones. Now she's a star, both on social media and at the zoo itself.

"It sounds like you're at some sort of a rock concert," Wendy Rice, the head keeper of African animals, said in a zoo video (below) about Fiona, "where some major celebrity has finally stepped onto stage. It's like she'll peek her head out and you can tell the exact moment when the public has a line of sight to see her because it's just an eruption of cheering and some people literally cry! I've seen people, like, get there and have a spiritual moment when they see Fiona for the first time.

"But she's just had such an impact on people's lives that they feel like they know her so intimately, and it's like a celebrity, and finally getting to see them in person, and you're like, 'Oh my God! They're real!'"

Local businesses and the zoo have cashed in as well, creating #TeamFiona apparel, limited-edition ice cream and even, of course, beer. The zoo has made almost $500,00 in licensing agreements, with most of that money going to hippo veterinary care, medical supplies and habitat improvements. Overall, the zoo reported to NPR that it estimates Fiona has brought in between $2 million and $3 million to the city.

Fiona also has raised awareness of hippos in general, according to the zoo. While hippo populations are not considered endangered, they are considered an "indicator species," according to Jessye Wojtusik, a scientist with Cincinnati Zoo's Center for Conservation and Research of Endangered Wildlife.

"[Hippos] can provide us with an idea of how changes in climate may be impacting their ecosystem and other animal populations. For example, if a population of hippos die off due to lack of water this is indicative that such drought conditions may not be normal for that region and also that many other species are likely suffering," said Wojtusik.

Birthday bash for a hippo star

Fiona the hippo underwater in December Fiona the hippo has come a long way in a year. (Photo: Cincinnati Zoo & Botanical Garden/Facebook)

Naturally, given her celebrity status, the Cincinnati Zoo is celebrating Fiona's birthday on Jan. 20 and everyone is invited. (Yes, her actual birthday is Jan. 24, but it can be tricky for folks to get to the zoo on a Wednesday.)

As to whether or not the guest of honor will make an appearance ... well, you know how fickle celebrities can be. Zookeepers will have some say in it: Hippos aren't allowed outside if it's below 50 degrees Fahrenheit (10 degrees Celsius).

Even if Fiona doesn't make an appearance, plenty of activities are planned and lots of goodies will be had, for zoo animals and human visitors alike. The humans can look forward to gifts, like hippo bathmats, Fiona-themed postcards stamped with her footprint and cake and ice cream. Discussions and interviews with Fiona's caregivers and the nurses from Children's Hospital will also be held. The animals at the zoo will get special enrichment "party favors" (toys and the like) to celebrate Fiona's birth.

The party is free with admission to the zoo, which is half-off regular price from Jan. 17 to March 9.