Here is just one bit from a fascinating article, most of which concerns bears learning to use a road overpass:
But over the years, critics and transportation planners, even some environmentalists have groused about the idea: Taxpayer money, building overpasses for bears? Is that really necessary? Would they even use the things? Researchers have been methodically studying the crossings since 1996 to answer this. And it turns out that, yes, animals deterred by fencing that now runs the full 70-kilometer length of the highway in the park actually cross the road an awful lot like a rational pedestrian would. It takes them a while, though, to adapt to the crossings after a new one is constructed: about four to five years for elk and deer, five to seven years for the large carnivores.
The full piece is here, and for the pointer I thank Philip Wallach.