The trailheads are full again. Across the mountain West and the Northeast, summer fills the backcountry with people, and it is prime season for crossing paths with a bear. Mostly, neither side is looking for the other. Two separate calendars, human recreation and bear biology, crowd into the same summer weeks, and a warming climate is changing when and why they meet.

For a bear, summer is the run-up to hyperphagia, the late-season binge that lays down the fat it needs to survive winter. The hunger comes on a schedule. A bear’s appetite builds through the summer and peaks in the fall, when a big brown bear may eat almost around the clock and take in tens of thousands of calories a day. People arrive on the trails as that hunger climbs.

More People, Longer Bear Years

Two things bring them together more often. One is us. More people live near and move through bear country than a generation ago, and in wealthy countries........

© Forbes