Senior year of highschool, I built a beaver habitat. As part of a class that partnered with Conservation Ambassadors, a group in Paso Robles that is dedicated to providing homes for displaced, abused, abandoned or permenently injured wild and exotic animals, we designed a habitat around the needs of Birtha and Burel.
The main criteria was that it needed to be rust proof, easy to evacuate the beavers if needed, and "beaver proof" (aka something they won't eat). We came up with a designed with a metal frame around all the edges to prevent gnawing, both a land and water entrance, and a ramp up to a sunbathing platform.
I led the fabrication of the beaver habitat, doing the welding and teaching my team members to use angle grinders to prepare the metal.