In a large tank filled with cold water, an orphaned beluga calf slurps and gulps with gusto six times a day.

Feeding time for this bouncing baby boy in the 24/7 critical care unit of the Alaska SeaLife Centre in the United States involves buckets, tubes and rubber nipples originally intended for livestock.

Tyonek, as the 11-week-old is known, guzzles formula made from powdered milk substitute supplemented with salmon oil and herring filets and pureed in a blender.

ALASKA SEALIFE CENTER The calf has gained 27kg since he was rescued after stranding in late September.

The calf was rescued in late September after stranding on a quicksand-like flat on the remote western edge of a frigid arm of water near Anchorage. And his rescue represents a collaborative, creative and extreme effort - by experts in Alaska and others who travelled thousands of miles to contribute to his care - to help save a species: the endangered Cook Inlet beluga.

With a population of only about 300, the species needs every individual. Even if Tyonek lives in captivity for the rest of his life, the baby beluga will provide data about health and behaviour critical to saving his species. But to get to that point, the whale must first grow.

So how exactly does one bottle-feed a whale calf? It actually takes three humans to prepare the delicious (to a beluga) and nutritionally sound meal and then bottle feed about a litre to the cetacean. In the wild, a baby beluga would swim alongside its mother to nurse.

ALASKA SEALIFE CENTER Tyonek's caregivers describe him as "very tactile".

"The calf swims up, and we present the bottle," said the centre's director of husbandry, Brett Long. Caregivers feed the baby around the clock, filling his belly with about six litres of the fishy formula each day.

It's working. Tyonek, whose name means "little chief" in the local language of the village near where he was found, weighed 61 kilograms when he was found. He's since packed on about 27kg more.

That progress certainly wasn't guaranteed when Carrie Goertz, the centre's animal health director, got to him.

The first person to spot him on that sunny Saturday was a keen-eyed officer from the National Oceanic and Atmospheric Administration. He and a pilot had flown in a helicopter that morning with Goertz to perform a necropsy on another whale that had died after stranding.

After dropping Goertz back at the centre in Seward, about 145 kilometres away, the officer caught sight of the baby beluga from the air.

The officer and pilot landed and tried to push the calf back out into the water. It didn't work, so they went back for Goertz.

When she arrived, she noticed damage to the beluga's fluke, or tail, probably from pecking birds and cuts from rocks. She guessed he'd been there at least two hours, but maybe as long as 12. But he was breathing, and his eyes were in good shape.

Still, Goertz knew the calf wouldn't survive without help, even if they could get him to deeper water.

She went into problem-solving mode. A pickup by boat would take hours and add additional danger. So Goertz and the NOAA officers scoped out the back of the helicopter and moved things around. They measured the calf - he was more than five feet long - and figured he'd fit, and then hoisted him inside.

It would not have worked if the animal resisted. But he didn't. They bolstered him with soft objects and took off for Anchorage. Two hours away at the centre, staff prepared for the calf's arrival, moving a young rescued walrus named Aku into another room.

Twenty minutes later, they transferred the little whale into a truck where he was made comfortable on a thick foam mat. A caravan headed south along the Seward Highway, which, for part of the way, hugs the harsh waters of Cook Inlet. Beluga experts from five aquarium partners - Georgia Aquarium in Atlanta, Shedd Aquarium in Chicago, SeaWorld San Diego, Mystic Aquarium in Connecticut and Vancouver Aquarium in Canada - immediately said they'd come to help, too, and some arrived within 24 hours.

"There is a significant effort in studying this population," Long said. Being in a position to respond quickly to individual animals, and possibly aid in the species' recovery, is crucial, he said.

The rescue was very unusual for the SeaLife Centre. It is often called on to rehabilitate seals, sea otters and other animals, but rarely cetaceans. A one-day-old beluga calf it took on in 2012 was in very poor shape and did not survive.

But Tyonek didn't have significant injuries. Caregivers focused on feeding him every two to four hours, tweaking the recipe for his formula and making sure he didn't sink in his tank - a common problem for exhausted and weak cetaceans.

Having lots of expertise devoted to the case helps, Long said. So does the fact that the calf already knew how to nurse.

Nobody manufactures beluga nipples, so the team has had to make do with some created for cows and sheep. Caregivers meet every morning at 8am to discuss Tyonek's daily weigh-ins, his temperature, and the ins and outs of his digestion (which they monitor by ultrasound). Ultrasound imaging also helps the team monitor the growth of his important blubber layer. And then there's the constant cleaning and sanitising.

"There's not a lot of idle time," Long said.

Now the baby is on a reliable schedule. He hams for the camera with a cuteness that rivals that of the world-famous Fiona the hippo. And in early November, he moved to a large outdoor pool.

Tyonek will stay in intensive care for another month and then continue to be looked after 24 hours a day. The National Marine Fisheries Service will determine whether he's a candidate for release. It's a long shot. In the wild, his mother would have given him two years of education in survival skills.

But for now, the baby beluga seems content with his caregivers. He head-butts them in the water and chirps and clicks to them. "He's very tactile," Goertz said. "Typically a beluga calf is touching his mom most of the time … He's definitely looking for that type of interaction."

She says he'll turn his body to get rubbed in a particular spot. "Not to be anthropomorphic," she said, "but you get the feeling he's saying 'Oh yeah, that feels good,' or 'Now scratch this spot.' "

When it comes to helping a terribly rare Cook Inlet beluga, Goertz added, "every day is a victory".