The River That Wolves Moved: A True Tale From Yellowstone

By: Mary Kay Carson
Illustrated by: David Hohn
Publisher: Sleeping Bear Press
Publication Date: September 15, 2022
ISBN: 978-1534111202
Reviewed by: Holly Connors
Review Date: September 25, 2022

Author Mary Kay Carson recounts the true story of how removing wolves from Yellowstone Park impacted not just the wolves, but all the wildlife and plant life in the park in her new book, The River That Wolves Moved.

This true story starts out with a simple statement - "This is the river that wolves moved." But how can wolves move a river?

Wolves, who were hunted to the point of extinction within the park, had been gone from Yellowstone for over 70 years. But they are now making a comeback, thanks to the park reintroducing them to Yellowstone in 1995. Without the wolves for all those years, their primary prey, elk, greatly increased in numbers. And the elk liked to eat willow trees, which they did, to the point that willows decreased in numbers. But that meant that the trees' root systems, which kept riverbanks in check, were missing and the riverbanks started to crumble. It was a domino effect that was never anticipated when wolves were heavily hunted and ceased to exist within the park's boundaries.

Written in the style of This Is The House That Jack Built, The River That Wolves Moved cleverly shows how the removal of just one species can have devastating effects on an entire ecosystem. Mixed in with the recounting of each change in the ecosystem brought on by the removal of the wolves, are "factoids" with additional details about what that change did to the environment. For example, on the page that shows how the riverbank was held in place by the root systems of the willow trees, the factoid explains, "A bank is where river meets land, where water touches dirt. Plant and tree roots grasp the soil, holding riverbanks in place..." Timely in its theme, The River That Wolves Moved would make an excellent addition to school or home libraries where students looking for books to help with research on ecosystem issues would find it a handy aid.

Quill says: The River That Wolves Moved is an educational book full of interesting facts about biodiversity and how the removal of one species can have a devastating impact on the ecosystem.