For the past several years, Disneynature has marked Earth Day by releasing a documentary* celebrating Mother Nature. “Bears” is the studio’s latest nature documentary with a twist*.

    The film opens with narrator* John C. Reilly introducing a mama bear, named Sky, and her two newborn cubs*, Scout and Amber. Soon after, Reilly tells the audience: Odds* are that only one of the two cubs will reach its first birthday.

    The film then follows Sky and her cubs as they travel from the comfort of their den* on a dangerous trip through Alaska in search of spawning* salmon*.

    Whenever Sky and her twin cubs survive one threat — an avalanche*, angry male bears, a hungry grey wolf — another danger threatens to kill one of the twins.

    Reilly lightens these stories by cheerfully narrating the cubs’ funny side. There’s plenty of imagined dialogue between the cubs and their mama, but Reilly pulls off the balance between educational facts and talking-animal shtick*. The humor is necessary considering the number of tense* moments.

    It’s not surprising that the often-jokey narration of “Bears” doesn’t focus on every side of a brown bear’s life cycle, as “March of the Penguins” or “Winged Migration” did for their avian subjects. For that, you’ll want to read the film’s interactive guides and activity sheets online.

    The movie is rated G, allowing audience of all ages, but there could be tears and protests* from young animal lovers — particularly during one scene, when a male bear pokes through fallen logs trying to eat one of the cubs. Don’t be surprised if older kids, on the other hand, want to Google “filial cannibalism*” after seeing the movie.

    That said, “Bears” is a story of triumph* and family. The wonderful cinematography, the funny narration, and the sometimes lively and sometimes threatening music are all used to showcase the lengths the wildlife kingdom’s most famously protective mother will go to provide for* her cubs. (SD-Agencies)