If you saw a sow with four cubs last year it was not the same sow bear with cubs you are seeing this year.
Bears only have cubs every other year. The cubs are born in January of one year then spend all of that summer with the sow. The sow does not breed that summer. Then come fall the cubs will den with their mother if the sow is still alive. When they all come out of the den the next spring they will travel with the sow for a short time before she starts to chase them away and the normal dispersal of the cubs begins.
Once the previous year’s cubs dispersed the sow will bred again that summer. The bear breeding season is June, July and August but the egg doesn’t implant into the uterus until November at which point the sow will head for a new den site and after a short gestation period of just a couple months the new cubs will be born. They will weigh less than a pound (about 13-14 ounces if I remember correctly) and stay in the den with their mother until late March or early April. The process then starts all over again, but bears only bred and have cubs every other year.
Maybe the cubs she had with her last year were much larger and she was just getting ready to kick them out when he saw them? Just sayin.
No, I guess I got my bears mixed up! There's another sow running around here with 3 cubs. There's alot of bear in my area, including 1 monster that must be close to 700 lbs. If I'm lucky I get to see him once or twice a year.