Markle successfully presents the astonishing world of Bracken Cave, the largest nursing colony of Mexican free-tailed bats. As they follow the activities of one mother and her newborn, youngsters (and adults) will effortlessly absorb the facts woven throughout: habitat, eating habits, echolocation, communication, predators, social network and childrearing. At the end of the baby’s first week, his survival is in the balance when his mother fails to return. But another mother who has lost her own baby steps in to care for him. Marks’s watercolor artwork is amazingly detailed—close-ups of the animals are lifelike, while wider-angle views give a realistic impression of the huge numbers of bats in the cave. Backmatter includes a list of resources, a bulleted list of brief facts and an author’s note explaining that research on the raising of Mexican free-tailed bats is ongoing, and new findings could refute what is presented here as fact. Nonetheless, this is a must for every nonfiction collection and bat fan. (Nonfiction. 5-9)