It's Fiona the hippo's birthday. She's already had a remarkable life.

"Is that what I think it is?" asks zookeeper Wendy Rice.

She can see the monitor over the veterinarian's shoulder.

Dr. Jessye Wojtusik performs an ultrasound on Bibi, a 17-year-old Nile hippopotamus at the Cincinnati Zoo and Botanical Garden. With the probe, Wojtusik zooms in on the murky image.

There is nothing else it could be, Rice thinks.

That's a spine. That's a ribcage.

"Oh my gosh," Rice says.

That's a heart. And it's beating.

Rice has just seen something on the monitor that no one else has ever seen. This is the first ultrasound ever performed on a pregnant Nile hippo.

This is the first of many firsts.

This story, Fiona's story, is familiar to most. The zoo – ever cognizant that this could still turn out badly – made the conscious choice to share this baby hippo's journey.

Still, there are moments none of us saw.

For her caretakers, these were scary and heartbreaking, joyful and life-affirming. And, after a year, after she's survived the worst, they can be told.

Fiona's story, after all, is now part of theirs. They will forever be the first to hand-raise a Nile hippopotamus.

Millions watched her grow this first year. They "hearted" tweets about her weight gain and Facebook videos of her showering or chomping on lettuce or dreaming.

Farting, too.

Fiona became so popular she got her own "show" on Facebook.

She was a New York Times Style section cover and a punchline on a late night talk show. Her face graced thousands of beer cans and ice cream cones and T-shirts and playing cards.

She inspired an online campaign for her to be Time's Person of the Year for 2017. She was that one neutral conversation topic at Thanksgiving tables across America.

January 24 marks her first birthday.

It was a life that started way too soon.

And it began with a phone call.

...

The ringing phone jolts Christina Gorsuch awake.

The camera focused on Bibi stopped working. "We don't know what's happening," the volunteer says.

Gorsuch has the video feed on her home computer. They've been monitoring Bibi since she started acting strangely the afternoon before.

She was swimming laps earlier than usual. She wasn't eating. Then her water broke.

It's about 2:15 a.m. on Jan. 24, 2017. From her home computer, the zoo's curator for mammals sees Bibi on the ground.

Gorsuch rewinds the footage, reviewing to see how long Bibi's been out of the water. Has she been rolling around? Is she in pain? Is she OK?

Her calf can't survive this, Gorsuch thinks, because it's just so early. It's been only 15 days since they first saw that heartbeat on the ultrasound.

Gorsuch reviews the unseen footage, then she switches back to the live feed.

It's 2:50 a.m.

A minute later, Bibi rolls over and a baby is born.

It wiggles its ears.

Dan, Gorsuch thinks. She's got to call Dan.

Zookeeper Dan Turoczi lives just five minutes away from the zoo. Gorsuch's house is seven.

They need those two minutes.

"She's had the baby," Gorsuch tells the zookeeper on the phone. "It's alive. Get to the zoo."

...

I don't know if this will work, Thane Maynard thinks.

The hippopotamus came six weeks too soon. She is 29 pounds. That's 25 pounds lighter than the smallest Nile hippo ever recorded.

The zoo director studied wild hippos in Africa. In his almost 40 years at the zoo, he's cared for hundreds of newborn animals. He's never seen anything like this.

She looks like a deflated football, he thinks.

...

Wendy Rice's heart stops.

The baby's head just went under water.

The hippo doesn't know what she's doing, Rice thinks.

Her neck muscles are so weak. Will she know to bring her head back above the water?

Her tiny face pops back up to the surface in the plastic pool. She wiggles her ears.

The hippo breathes in. Rice exhales.

She's got a shot, Rice thinks.

...

It's January 31, and Rice is on the 6-10 p.m. shift.

She wears medical scrubs. She lies on a pile of pads and towels and blankets on the floor of a bathroom in the Hippo Cove building.

The hippo's temperature is 93 degrees. She needs to be closer to 98. The zookeeper is doing her best to transfer her body heat to the baby the staff now calls Little Spoon.

The hippo is 2 feet, the length of Rice's torso. Little Spoon's skin feels like a plum.

Someone is scheduled to be with Little Spoon every hour of the day. Her survival is still minute by minute.

They don't know what to expect next. They are learning as they go, and they are writing everything down.

Rice opens the zoo's Facebook page on her phone. Thousands are watching, liking, replying to the staff's posts about the week-old animal next to her.

There's a video of the baby squirming in the pool for the first time. The next day, there's one of the staff milking Bibi.

Rice reads the Facebook comments out loud.

"Continued prayers....thanks to all working so hard with this hippo family." "Hope she makes it! She's so cute!!" "So glad to hear an update. Rooting for this little girl!"

When Rice moves an inch away from her, Little Spoon crawls an inch closer.

...

The timer on her phone is at one minute.

Tami Ware started it when the hippo they named Fiona began holding her breath.

This is called a dive response. All hippos do it. Her species spend most of their lives under or in water.

But her lungs are not fully developed and this is not while she is under water. She is on land and this breath-holding is an instinct.

It's early February. She's not even supposed to be born yet.

Fiona's face fades to white. She is not strong enough to expel the carbon dioxide building up in her body.

Fiona is poisoning herself, and there is nothing Ware can do.

The zookeeper's timer is now at two minutes. Ware is on her knees over Fiona.

"Wake up!," Ware says. "Fiona, wake up!"

It's like Fiona's in a trance. It's like she is somewhere else.

The phone timer is at two minutes and 15 seconds.

Fiona gasps.

Ware does, too. She's been holding her breath.

More: Feeding Fiona: The science behind milking a hippo

....

On February 17, Ware greets two nurses from the Cincinnati Children’s Hospital Medical Center at the zoo's entrance.

Fiona is teething. She is no longer drinking milk from the bottle. The zoo staff cannot get the fluid-delivering IVs to stay in her body. They can't find veins in her skin that now feels like a cantaloupe.

She is dehydrated. She is dying.

The nurses carry ultrasound equipment into the hippo building. They use it to find small veins on small humans.

Ware can't go with the nurses to Fiona. The zoo's veterinary staff are with her now.

Ware visits the other animals in the Africa exhibits today. This is her job, but this is also what she needs. It will help her not think of Fiona for a few minutes, she hopes.

She sits with the lions first. Their deep gaze makes Ware feel like they understand what she is saying.

"You're so pretty," Ware says to the lioness Imani. "How lucky you are. How lucky I am to work with you."

...

Rob Meyer looks at his sketch. He grins widely.

This is it, he thinks.

The Cincy Shirts artist takes a sip of his coffee. It's February 25, a Saturday.

He works at his kitchen table in his Anderson Township home. It just took him a half hour to complete that now-famous outline.

Just a couple of days ago, zoo officials told the Cincy Shirts owners that Fiona is improving.

Nurses from the Cincinnati Children’s Hospital found a vein for the catheter a week earlier. She received the life-saving fluids.

She is gaining weight again. She is wiggling her ears again.

And that's how Meyer drew her today, as a happy, healthy hippo.

She smiles. His Fiona is somehow both skinny and chubby. She is a wrinkled potato.

He has Fiona photographs that the zoo sent over. He has looked up pictures of hippos on Google, too.

Another inspiration is curled up at his feet.

That's Lily Munster. She is his black pug. She is just less than 30 pounds, Fiona's birth weight.

She is squishy. She's sassy. She shoots a mean side eye. Just like Fiona.

Meyer takes another sip of coffee.

The funny thing about animals: One man's dog is another man's hippo.

...

Thane Maynard raises his binoculars toward the sky. It is the first week of March.

The zoo director is on a deck at a lodge in northern Belize. This lodge is so remote that birdwatching is the only thing to do here.

He lowers his binoculars. He's heard something.

"I'm sure glad they've got WiFi because I've got to keep up with baby Fiona," a nearby woman says to another

He introduces himself.

"Whoa, you know baby Fiona?" she says.

More: Fiona the hippo dazzles in front of the cameras

...

Cammy Lorentz slips the paper she has typed into the scrapbook page, right above a picture of Henry and Bibi.

"You were so excited to see your mom and dad that you decided to arrive a little early (don't worry – I did the same thing when I was born!)," it reads.

Cammy is in the third grade at Summit Country Day School.

She gets very excited when there are new animals at the zoo.

She makes scrapbooks for people she loves and she loves Fiona.

She didn't know anything about hippos when she was 7, but now she is 8, and she knows a lot of things about hippos. Hippos eat grass. They can weigh 4 tons.

It is an afternoon on a March day. Cammy is in her kitchen in Hyde Park.

She cuts out the zoo staff's photos of Fiona resting on a keeper's lap and a couple of her drinking.

She pastes the photo of herself with her Flying Pig 5K medal, right next to the one of her about to dive into a swimming pool. A few page flips later, there's a smiling Cammy, then a toddler, atop her father's shoulders during a zoo visit.

The book will help Fiona have confidence, Cammy thinks. Cammy was born prematurely, and she runs and she swims now. She wins races.

Cammy picks up her pencil.

"Dear Fiona, You are awesome. I am so glad you are here along with your mom and dad. The Cincinnati zoo is the best place to live," she writes.

"You are going to be stronger and faster then (sic) me! My favorite place at the zoo is the hippo exhibit. You are going to love your new home. Love, Cammy."

...

There's almost every photo we have released of Fiona in this, Rice thinks as she flips through the pages.

Cammy's book has just arrived in Fiona's mailbag at the zoo.

A couple of months ago, the keepers started a list of all the people who wrote them so they could send thank you notes. But the few letters turned into hundreds and then into thousands.

Some 16,000 people sent the weeks-old hippo valentines in February. Fiona's love letters filled two mail bins Feb. 14.

...

Sam Stryker scrolls through the Cincinnati Zoo's Instagram and Twitter feeds.

The Buzzfeed editor watches clips of Fiona prancing around in the water, shaking her booty when she gets out of the pool.

She is vibrant and positive and so self-aware, Stryker thinks. She performs for her fans. She has a stage presence.

That's why he's seen Fiona on pop culture tastemakers' Twitter feeds this summer, he thinks.

She's got a pop star personality.

On July 26, he tweets about her for the first time.

...

Fiona's head pops above the water's surface. She looks directly into Sam Stryker's iPhone's camera.

This is why he took the redeye flight from Los Angeles to Cincinnati: To take a selfie with Fiona.

Stryker is next to zookeepers as they toss lettuce to her from the behind the rock barrier at Hippo Cove.

It's October 6, and Stryker's family has just made a last-minute trip to Cincinnati.

This is not a Buzzfeed assignment. He's here because, just the week before his mom texted him, "I would love to visit Fiona."

This is surreal, Stryker thinks, staring at the mini-hippo. It's like when he met a Kardashian.

...

Hayley Roll hands her iPhone to the mother standing in line behind her at Hippo Cove.

It's October 8 and the Cincinnati Children's radiology technician is at the zoo with her boyfriend, Nick Kelble. She wants a picture of herself and Kelble and Fiona.

Fiona is kind of their thing. They texted her videos to each other all the time when they were apart, as Roll finished her last semester at Bowling Green State University and Kelble was at the University of Cincinnati.

The mother agrees to snap the photo. Roll turns back around toward Kelble.

He is on one knee.

"Hayley Danielle Roll, will you marry me?" he says.

...

"Thank you."

Nick Kelble types that over and over again. He will type it a hundred times.

People from Sweden, Chile, Brazil are messaging him and Roll on Facebook. They are strangers, and they are congratulating the couple on their engagement.

It's been two weeks since Kelble pulled a diamond ring out of his pocket, a stranger took a photo and Roll posted it on her Instagram account.

That moment grows. It appears on US Magazine's website. CBS News. The Today show.

When Sam Stryker writes about the couple for Buzzfeed on October 24, he says this: "Fiona The Hippo Photobombed This Couple's Engagement And I Believe In Love Again."

That same day, Kelble and Roll's photo appears in the opening monologue on "The Tonight Show."

"Yeah, Fiona was like, 'Always a bridesmaid,'" Jimmy Fallon quips.

...

It's Christmas at Sam Stryker's family home in New Cannan, Connecticut.

A Fiona keychain hangs on his stocking. A Fiona ornament dangles from a tree limb. The presents below are wrapped in Fiona paper.

Stryker wears his red “I want a hippopotamus for Christmas" sweatshirt. It's the latest variation of the Fiona cartoon Rob Meyer drew on his kitchen table.

Fiona looks like she's been cross-stiched with white thread. An outline of the Cincinnati skyline is at her back.

In three days, Buzzfeed – a site with hundreds of millions of readers – will publish Stryker's sixth Fiona post.

"17 Times Fiona The Hippo Was The Best Part Of 2017."

...

Zookeeper Dan Turoczi is cleaning when he hears banging.

Fiona and each of her 632 pounds slam into the wooden slats of the door behind Hippo Cove.

She wants to play.

Turoczi rubs her through the door. She feels like a slimy avocado.

She is still thousands of pounds away from being all grown up, but she is far too big for Turoczi to safely share her space. Fiona doesn't need him to be close anymore, either.

Not like almost a year ago, when Fiona was 10 minutes old and Turoczi became the first human she'd meet. He was the first to save her life.

It's now Jan. 10, 2018, but it's 60 degrees out. That's warm enough for Fiona to go out on exhibit. Her fans wait on the other side of the glass.

Turoczi walks to the rock wall edge on the left side of the exhibit.

"Fi! Fiiiii!" he says.

The zoo staff now manage Fiona like other hippos, but she will never be like other hippos.

Zookeepers update Fiona protocols daily. They are learning as they go, and they are writing everything down.

Today, she is in a zippy mood. So when Turoczi calls for her, she comes out from the building. She bounds toward him through the water.

She meets him at the wall.

He bends over the rocks. She pushes out of the water. Their faces touch.

From the other side of the exhibit glass, it looks like a kiss.

It might be.