BILLINGS, Mont. — A 72-year-old man picking huckleberries in Montana shot and killed a grizzly bear after it attacked in a surprise encounter and injured him badly enough that he had to be hospitalized, authorities said Friday.

The man was alone on national forest land when the adult female charged him Thursday. He suffered significant injuries before killing the bear with a handgun, Montana Fish, Wildlife & Parks officials said.

The bear was likely reacting defensively to protect cubs,…