Summer Brings People And Bears Together. A Warming Climate Is Reshaping The Calendar

A longer, busier overlap would still be quiet if the bears were well fed, and most years they are. The trouble comes in the years the wild food falls short. Warming can nudge spring growth earlier, leaving the berry and nut crops bears rely on exposed when a hard freeze follows. In northwestern Nevada, the years with a late final freeze brought more conflict with people and more bears killed by managers.

Drought does similar work. In New York, the serious conflicts cluster from July through September and run higher in dry years. One of the clearest cases is British Columbia's salmon coast. Halve the salmon run, researchers found, and bears killed in conflicts with people rise by about a fifth. A bear short of wild food in August starts searching, and the search can lead toward town.

None of this makes a warming climate the whole story. In much of bear country, more people and recovering bear populations simply put the two on the same ground. Vermont's black bears now run well above the state's management target, and the crowds in the backcountry keep growing. The bears at the edge of town are not necessarily the hungry ones. When researchers in Scandinavia studied brown bears around settlements, they found little sign the animals came in for better food. Much of what looks like desperation is closer to opportunity and overlap.

An encounter almost never becomes an attack. People and bears cross paths many thousands of times each summer, and the great majority of meetings end with the bear wandering off. Brown bears, more dangerous than the black bears most hikers meet, were behind about 664 attacks on people worldwide from 2000 to 2015, a few dozen a year across three continents. About half the people hurt were out for recreation. The risk to any one hiker on any one day is very small. The attacks that do happen turn on particular bad luck, a surprise meeting at close range or a female defending cubs. Carrying bear spray in grizzly country and making noise on the trail shrink even that.

The makings of a bad bear year can often be seen coming, in a damaging spring freeze, a failed berry crop or a weak salmon run. None of that is a reason to stay home. Just keep your wits about you in late summer, when the bears are hungriest and the trails are busiest.