Giffen Goods

Biological Parallel

During severe winters, deer and moose strip bark from trees—a nutritionally inferior food that damages teeth and provides minimal calories. Paradoxically, as winter deepens and bark becomes harder to access (frozen, covered in ice), they consume more of it, traveling farther and working harder to obtain this degraded resource. Deep snow makes movement to better feeding areas prohibitively expensive, trapping them in local patches where bark becomes the only accessible option. As the "price" (effort cost) of bark rises, consumption increases because better alternatives are economically unreachable—a textbook Giffen good driven by mobility constraints.