Opossums are marsupial (carries its young in a pouch). They breed in late January or early February (some will breed again in May). Females have one to two litters per year. The average litter size is seven to eight young. The female gives birth to underdeveloped young approximately 13 days after mating. At this stage, the young are about the size of a bumblebee and they must crawl to their mother's pouch where they continue to develop. Young opossums leave the pouch when they are two to three months old but remain near the female so that they can return to her pouch to nurse. By the time they are three months old, they will be weaned and on their own. The ones you found sound like they are recently weaned and on their own (about 3 months old). Sometimes the young will buddy up together for awhile after the female has weaned them and they are on their own. The female is probably not still in the garage, but you could just use a broom to Gently direct her out the door if she's still there. They hiss and show all of their teeth, but opossums are pretty much all show.
