Bears mate in late May, June, July or early August, although the busiest mating season is in June and early July, with chiefly regional differences. Black bears are not able to breed until they are about two and a half years old. Since cubs will often remain with their mothers for two winters, sows do not breed every year. In the summer following their second winter hibernating with their mothers, either the mother or a would-be suitor will run the cubs off, after which they are on their own. Siblings might remain together for another year or longer, but bears are generally solitary animals.