Here is an interesting item from the Hungry Horse News Yesterday column. This was the year after the fatal bear attacks in 1967 at Trout Lake and Granite Park and two years before my first summer in Glacier:
"March 22, 1968
Glacier National Park wrote a new leaflet for visitors about bears. It noted that “while grizzlies are the most fearsome animal” black bears should also be avoided. In addition, it urged people to make noise while hiking and recommended carrying bells or a can with pebbles to hang from your belt. Perhaps most interesting, it urged women who were having their menstrual cycle to avoid the backcountry. The menstrual cycle theory has since been debunked. The Park today doesn’t urge people to carry bells, but it does still tell people to make noise while hiking."