National Geographic's gloriously photographed documentary informs and entertains but misses out on the affecting majesty of its clear inspiration, March of the Penguins. Experienced naturalists Adam Ravetch and Sarah Robertson shot hundreds of hours of footage in the frozen habitat of polar bear cub Nanu and walrus calf Seela as they battle the effects of global warming in their hunting ground. Narrated with breezy informality by Queen Latifah, the script was co-written by Kristin Gore, daughter of former US vice-president Al Gore (An Inconvenient Truth) and brings an authoritative element to the environmental plea finale. But the accent here is on the cute and cuddly, with upbeat pop songs on the soundtrack (We are Family) and comedy mined from the animals' recognisably human characteristics, while any real tragedy is tempered with an upbeat Disney sheen.