- The trend is tied to a hunting regulation that protects family groups from hunters. It's illegal to shoot mother or cubs when they are together.
"For females, if you leave your cubs at one year and a half, then you become a target during the next hunting season," explains Pelletier. But "if you stay for a bit longer with your cubs, you're protected an extra year. The hunting is filtering out the females that keep their young for a smaller amount of time."
The analysis used decades of data collected from tagged brown bears in Sweden — the European cousins of North American grizzly bears. But the findings may be applicable outside Scandinavia, in any place where hunting rates are high. Hunting policies that protect mothers with cubs are widespread. In the U.S., many states have such laws in place for a variety of game animals.