Animals facing threats from human encroachment are featured in these offerings from the Our Wild World series. Prairie Dogs looks at critters considered a keystone species by scientists, linked to the survival of about 40 other species. Horse-lovers will gravitate to the doe-eyed bays on the cover of Wild Horses, which introduces readers to the scattered herds of mustangs still roaming the U.S. Both books spend a great deal of time on these animals' fascinating social systems, from the bands of mares led by a single stallion to prairie dog towns subdivided into coteries. The prose is consistently clear and lively, although Lorbiecki's breathless marveling at prairie dogs' language of chirks, yips, and other vocalizations may lead children to anthropomorphize more than is warranted.