What Are Sea Mammals?

Gr 3–6—Each title explores a broad group of ocean life, introducing general characteristics along with specific traits of selected examples. Fish, for instance, describes attributes such as scales and cold-bloodedness that are shared by most fish, but also includes a short section on sharks and a quick look at several unusual members of the class. Sea Invertebrates includes examples of mollusks and crustaceans; both are covered in separate books within the series in more detail. There are many bits of information on multiple topics, which could challenge some readers, but the plethora of facts is helped by logical organization and writing that is generally smooth and concise. Half-page photographs on each page and occasional diagrams offer solid visual support. Text insets include vocabulary definitions and reader-directed questions to encourage critical thinking. Closing pages look at human interactions, survival status, and prospects for the future of each group.