The Cascade Snapshots: A beaver tale | Gap years are mythical creatures | Slash the week By Andrea Sadowski Do beavers just look at a roaring river and think “this has got to stop?” Why do beavers need to build their habitat right over a running body of water? These furry little engineers build dams to create homes for multi-generational family units, serving as protection against predators. The ponds these dams create help sustain other species as well, like Sandhill cranes, mule deer, and juvenile fish; beavers are considered a keystone species for their ability to change a habitat to suit not only their own needs, but for other creatures in the animal kingdom. The slowing of rushing rivers cools the water and makes it easier for the land to absorb, preventing droughts.