Did you know that a groundhog can make whistling sounds? These sounds warn other groundhogs of danger. Find out more in Groundhog, one of the titles in the Backyard Animals series. These books introduce readers to the many animals that can be found in and around the backyards of North America. This is an AV2 media enhanced book. A unique book code printed on page 2 unlocks your interactive eBook. This book comes alive with videos, audio, weblinks, slideshows, activities, and much more.