Explores how whales help to maintain a healthy ocean and, by extension, a healthy and biodiverse planet. Whales are ecosystems engineers -- animals that create, modify or maintain a habitat or ecosystem. In its lifetime, a whale can improve our planet's health by reducing the amount of carbon dioxide, one of the most abundant greenhouse gases, in the atmosphere. How? Whales store a significant amount of carbon in their bodies. When a whale dies and sinks to the ocean floor, that carbon remains locked away, deep in the ocean's sediment. For centuries, commercial whaling decimated whale populations around the world. Many never recovered, but in the decades since whaling stopped, some populations finally seem to be rebounding. This is great news for whales, and recent studies have shown that this could also be great news for humans as we struggle with the challenges of climate change.

Includes index.

Whales of the world -- Catching dinner -- Whale food webs -- Living on sunshine -- A poop pump -- A food chain mystery -- Migration: The ocean's mix master -- Whales help the planet -- Things are heating up -- Carbon is key -- Carbon on the move -- Storing carbon -- The carbon conundrum -- Whales to the rescue -- Help whales help the planet -- Glossary -- Resources.