Pam Carson, age 13, of Williamsport, Pennsylvania for her question.

How big are baby opossums?

A newborn opossum is just about as big as a kidney bean. He is naked and blind, but not helpless. As soon as he is born, the mini baby clings to his mother's fur and makes his way to the pouch on her tummy. He is one of a litter of six to twenty brothers and sisters. Inside the pouch, the mini infants find nipples to feed only thirteen of them. So if the litter is extra large, some will be doomed to starvation from the start.

The brood of bitsy babies huddle inside their pouch for about two months, feeding and sleeping and developing. Then the furry youngsters like to ride around outside, clinging to the fur on their mother's back. She is no bigger than a smallish dog and with a dozen mouse sized babies on her back, the little mother can hardly waddle. However, in another four weeks or so they are rat sized teenagers, all ready to go off to live lives of their own.