Abandoned by his mother and seemingly left for dead, a yearling grizzly bear cub at Katmai National Park and Preserve has been adopted by another female bear in a turn of events that seems more like it belongs in a Disney movie than in the wild.

A young bear once feared lost is alive and flourishing thanks to the efforts of a sow named Holly.

Rangers describe Holly as a supermom, even if she doesn't drive a minivan or attend to soccer practice. She is simply a Katmai brown bear between 18 and 20 years old adept at raising young bears. She gave birth to a single cub this spring in a land where bears often give birth to two or three to guard against what is the almost inevitable loss of one or more before they are weaned.

Holly, in an act of rarely witnessed bear love, appears headed toward hibernation with the adopted cub and her own cub in tow.

"It is fascinating to watch," said Troy Hamon, chief of management and science at Katmai. Park employees know of only one other similar situation, "years ago" on Kodiak Island.

Holly is officially known as brown bear 435. She is described as a sometimes "nervous mother'' known for taking her cubs into trees for protection and nursing a yearling with a broken leg back to health. But she topped that this year when she fed the male yearling along with her own 9-month-old biological cub, whose gender is as yet unknown.

"Anytime the sow has cubs, it is a strain on her system and having to feed them, nurse them or share food with them could drag her health down, and it's possible they won't make it through the winter," said Roy Wood, Katmai's chief of interpretation.

But Wood also said it could be a good move on the sow's part. The yearling will give Holly and her cub another warm body to den with, which might increase their chance of surviving the winter.

The adopted cub is estimated to be about 21 months old. He was the one of three cubs born to sow 402 last spring. By the end of summer 2013, 402 had lost one cub, possibly killed by another bear. Mature bears often kill the cubs of other bears in the wild. When 402 returned this year, she had only one cub with her, the one she later abandoned.

Rangers thought the abandonment might be temporary. Wood said the first separation came July 1, but 402 and the yearling reunited before the day was over. "You know, we thought 'all was well. She won't let that happen again,' but then a very dominant bear began courting her at the (Brooks) falls."

Brown bears go through "somewhat predictable cycles," park biologists say. Sows usually stick with cubs for two to three summers and den with them one last time before pushing them away in the spring. While they care for their cubs, they nurse, which typically prevents them from going into estrus.

And although 402 shouldn't have been in estrus, a potential opportunity for breeding seems to be one of the only explanations for the dominant male bear, the unnamed 856, to find her interesting. After about two weeks of not nursing in summer, Wood noted, the mother will go into estrus.

After the yearling's mom dumped him to run off with a male bear, the yearling began spending nearly 24 hours at a time alone in a tree by Brooks Falls. Sometimes his mother would come past, but eventually even that contact ended.

"He would come out of the tree, wander around and then go back into the tree to get away from the falls, where all of the big, scary bears are."

By the end of July though, he'd come out of the tree and was spotted at Margot Creek, about 10 miles from the falls, trying to fish. Oddly enough, Holly was with him. It was the first sign that the yearling had formed a relationship with Holly. Wood laughed and added that the young bear did catch a fish, but he believes it was dead or near death.

"We still count it though,'' he said.

By September, the yearling had made progress and had a new mom to see him through winter. He, Holly and her cub were acting like a family. The yearling had honed the fishing trade and was almost as swift as his adoptive mother at nabbing a catch. He was also sharing his catch with Holly's biological cub -- another rarity among grizzlies. Typically only biological siblings will share food as young bears.

Despite biologists' initial concerns that Holly's choice to adopt the young male grizzly would put a drag on her health and her cub's health, Wood said all three bears are looking healthy. Holly, one of the "fattest" bears in the park when she is without cubs, is described as "still quite a porker." And her adopted son has steadily gained weight since his late July adoption.

Katmai biologists still have many questions about the situation. Their observations indicate 402 was in estrus, but they are unsure why she would be. If 402 did return to the Brooks Camp area -- where she was last seen at the end of July -- would the adopted yearling still treat her as its mother? If so, would the biological mother accept it, and how would Holly react?

"We don't know what caused Holly to adopt him. It may just be a powerful maternal instinct," said Wood.

Holly is already credited with nursing a cub from a previous litter back to health in 2007. "Backpack," named so after the newborn was spotted several times riding on Holly's back, broke his leg in 2007. Holly said the sow brought the injured cub food, was patient while they traveled, helped it cross a river and "was as loving and doting" as a mother could be.

Holly is the only reason Backpack, bear 89, survived, Wood said. The bear is now a thriving fisher at the falls.

"It was a difficult time because a lot of people thought we should euthanize him (Backpack) or at least have him captured so he could be taken to rehabilitation facility, or zoo, but that is against our policy,'' the ranger said.

Park policy prohibits officials from interfering with the bears' natural cycle no matter how ugly the outcome may be. The intent is to preserve the bears in their natural habitat.

Wood said that when the yearling was abandoned there was a debate about what to do, but after watching the yearling -- once described as being on "death's doorstep" -- survive, they are happy they left his fate in the hands of nature and the paws of a super-mom sow.

"What she did is almost heroic," said Wood. "We have another abandoned cub and we keep wondering if she will say 'what the heck' and take it too. But we don't know who it belongs to. It is actually catching fish but it is also a spring cub so it hasn't had the benefit of going to hibernation with its mother yet."