Possums are North America's only marsupial and have tremendous numbers of young and more teeth any other furbearer in North America.
The bottom picture shows 7 baby possums in a tea spoon at about the time they first make it into their mother's pouch. The middle picture shows the location of the pouch. Pouch mortality is fairly high, and usually only five to eight baby possums survive to peek out in the world two months after being born. Most possums die within the first 9 months of life (killed by cats, dogs, cars, fox, poison, disease, traps, and coyotes) and few make it to age three.
A typical female possum will have two litters a year, each with as many as 18 young. The gestation period for a possum is just 13 days -- the shortest gestation period of any mammal in North America.
Opossums prefer low, damp, wooded streams and swamps. They are nocturnal, and will shelter in hollow trees, firewood racks, brush piles, groundhog burrows, and crawl spaces under houses and outbuildings during the day. Possums are very common in suburbia where they often dine on school-yard refuse, dead squirrels in the road, and cat and dog food left out on people's stoops. Complete omnivores, their tracks looks like those of a space-alien, while their scat can come in any shape and color.
Though possums will hiss a great deal, they are not very formidable creatures, as their teeth are too small, their brains too small, and their response time relatively slow when compared to raccoon, fox, or groundhog.