(Newser) – An Alaskan brown bear that had already rescued one cub after it broke its leg has once more become Katmai National Park and Preserve's resident hero. Holly—officially known as "brown bear 435" but described by park rangers as "supermom"—took in an abandoned grizzly cub as her own after the cub's real mother ditched him at a waterfall over the summer to run off with a male bear that was wooing her, Alaska Dispatch News reports. The yearling has even been spotted sharing food with his new mom's biological cub, which rangers say rarely happens between bear cubs that aren't related.

The adopted cub, thought to be about 21 months old, was abandoned near Brooks Falls in July. He would wait for his mother for hours near the falls, and she'd occasionally show up, but then she stopped coming. Officials couldn't intervene—park policy mandates letting nature take its course—so they were glad (and amazed) to see Holly teaching the cub to fish one day, taking over where the cub's own mother had left off. They've been inseparable since, though Katmai authorities suspect Holly may have an ulterior motive: stockpiling another warm body to help her and her cub survive the harsh winter. Still, "we don't know what caused Holly to adopt him," says Katmai's chief of interpretation. "It may just be a powerful maternal instinct." (Read more uplifting news stories.)

