"Tilly" is well-written mix of factual information about the North American River Otter, interspersed with the story of a young river otter named Tilly. It's illustrated with color photos of wildlife and drawings of appropriate animals throughout the story.
And even better: Tilly doesn't lose any family members, undergo any traumas requiring some sort of otter GPS to find her way to her otter home, get captured by evil fur-hunting humans, or nearly starve looking for food. She leads a nice, steady otter life.
She sees other (helpfully drawn or pictured) animals. She escapes the clutches of a (helpfully pictured, never close by) bald eagle thanks to the warning of a mature otter. She eats appropriate (helpfully pictured) otter food.
All in all, a harmless 54-page nonthreatening story with accurate details about lutra canadensis. It even includes the international otter survival fund contact info. Seriously, who could ask for more?