Here’s a nice video though of a mother and her cubs eating grubs and bugs in a rotting log in Yosemite.
If you come up on a situation where there’s a female bear you really don’t want to approach them whether you can see cubs or not. If there’s a cub lying in the brush or up a tree close by and you come between it and the mother you might be in trouble. Sows are known to charge people for no better provocation than they were in the area.
Hey they’re wild animals, what can I say? I see the same thing all the time when my brother charges someone at the all you can eat pizza buffet just because they got between him and the pepperoni with mushrooms.