History-making mother bear could be big Fat Bear Week 2026 contender

In 2022, Bear #910 adopted her sister’s yearling cub.
a bear walking by a wave on the beach
Bear #910 spotted in beach-ready form in 2024. Image: NPS image by Cory Cravatta

We are mere weeks away from Fat Bear Week 2026, but the brown bears (Ursus arctos) gorging on salmon at Katmai National Park and Preserve in Alaska are already showing off that beautiful bulk. Based on a recent video posted by explore.org, Bear #910 might be a major contender for this year’s competition.

Bear #910 is a female brown bear that was first spotted in 2019 at Katmai’s Brooks River. She is about 10.5-years-old, has large, blonde, floppy ears, which can help viewers pick her out of the crowd on the live cam set up in the park. 

Bear #910 is also a particularly unique mother bear. Between mid-August and October 2022, she adopted her sister Bear #909’s 2.5-year-old female yearling cub (a one- to two-year-old cub still with its mother), while she herself had a spring cub (a first-year cub that was born over the winter and emerges in the spring). An adoption like this is an exceptionally rare event in the wild, but it has also been observed in polar bears. The pair was frequently seen fishing together with their cubs throughout 2023 and 2024 and a paper on their story was published in the journal BioOne in 2025. 

Sisters 909 & 910 Unique Relationship | Memorable Moments in Bear Cam History thumbnail
Sisters 909 & 910 Unique Relationship | Memorable Moments in Bear Cam History

Most bear mothers generally keep their litters separated, and this year’s season was an example of why they tend to stick to themselves. On Tuesday, July 28, the live-cams captured a young brown bear cub being killed and eaten by an unrelated mother bear (Bear #806). The deceased cub was born this spring, and was one of Bear #909’s cubs. Bear 909 started this season with two cubs, but has now lost both. 

On Sunday, August 2, one of Bear #335’s (also known as Jolly) cubs died, after following three unrelated cubs up a tree. The mother of the cubs already in the tree attacked Bear #335’s cub, who did not survive the encounter. The identity of the mother bear who killed the spring cub was not confirmed. 

Following the first cub’s death, naturalist Mike Fitz and park rangers Christine Loberg and Sarah Bruce hosted a chat about the incident. The team said that while infanticide by female adults does occur, this is likely the first documented case occurring at Brooks River. While there is no single answer as to why mother bears are killing cubs, some experts suspect bear adoption, food scarcity, and fights for dominance all play a role. 

During Fat Bear Week 2025, she lost to Bear #856 in the second round of voting. Voting this year. The competition this year is scheduled to begin at the end of September.

 
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Laura Baisas

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Laura is Popular Science’s news editor, overseeing coverage of a wide variety of subjects. Laura is particularly fascinated by all things aquatic, paleontology, nanotechnology, and exploring how science influences daily life.