The possum is a member of the marsupial family and the only species of marsupial found in North America. Its life span is only two to four years -- the shortest of mammals its size. It is highly adaptable, social and nocturnal. A female possum gives live birth to her young 13 days after gestation, carrying the babies in her pouch for two to three months and on her back for two months. The male makes clicking sounds with his mouth to attract the female during mating season. According to the Opossum Society of the United States, December through October marks the breeding season for the Virginia opossum, with babies typically being born between February and June.
Turn the possum over on its back and look at the genital area.
Identify the physical characteristics, observing the stomach and lower region of the body. Females have a smooth opening above the tail and a pouch near the lower abdomen. The pouch is a small fold of skin with a small opening where the relatively undeveloped fetuses are protected, and which covers the nipples.
Observe the lower body near the tail. The male's testicles, visible also from the side or back of the animal, become distinguishable seven days after birth, becoming large and furry. The male also has a bifurcated (fork-shaped) penis.