The gray whale lives most of the year in the Arctic Ocean, but the female travels into the Pacific Ocean off California's Baja Peninsula to calve. After approximately three months, mother and baby must make the treacherous trek back. The book is written in informal storytelling fashion; facts are here but presented under the guise of a story. The rather cute ending belies the dangers the whales will face on the return migration (and, technically, they are crossing seas, not sea per the title). Leonard's vivid color double-page acrylic underwater paintings illustrate. Back matter includes Common Core critical-thinking questions. Part of a new series, Extraordinary Migrations, other books in the series feature the monarch butterfly, Christmas Island crabs, and emperor penguins.--Petty, J. B. Copyright 2015 Booklist

A gray whale feeds heavily in her arctic home, preparing for her annual migration to warmer waters off Mexico. Once there, she has a baby, then in a few months, they return north. The clear though uneventful text is joined by full-page acrylic illustrations, which, while not adding much context apart from a single map, are accurate and realistic. Reading list. Glos., ind. (c) Copyright 2015. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.