Male bears will kill another bear's cubs on purpose, so the mom is ready to mate again in a few days instead of up to two and a half years. Some mother bears figured out how to protect their cubs from it. They started living closer to people. That cub with her paw up is learning to stand, which is how bears check for danger over tall grass. Brooke Bartleson, who filmed her, said cubs this age are so wobbly they flail their arms just to stay upright. That's the "wave." She tipped over a few seconds later. She has good reason to learn fast. Park biologists at Katmai in Alaska figure only a third to half of brown bear cubs make it through their first year, and other bears are a big part of why. One study in Interior Alaska found 69% of cub deaths happened in a 17-day stretch in early June, right in the middle of mating season. So researchers in Sweden set out to see what the successful moms were doing differently. They put GPS collars on 26 mother bears and tracked them from 2005 to 2012. Sixteen of them raised their cubs and ten lost them. The moms who kept their cubs lived about 780 meters from the nearest people. The moms who lost theirs stayed around 1,210 meters away. Male bears avoid humans, and the mothers seem to know it. The ones who made it moved toward villages full of bear hunters, because the woods full of male bears were worse. Now go back and look at the mom in that first photo. She's got her head down eating grass while someone stands right there filming her kids. I can't tell you what was going through her head, but now you know who she was keeping an eye out for. We all grew up being told to stay far away from a mama bear with cubs, and some of those mamas decided the best place to raise them was right next to us.