Wondrous Wildlife
By Vern and Lori Gieger
Nocturnal Nomads

     These under appreciated mammals are the only marsupials on our continent. The opossum is one of the world’s oldest living mammals. Structurally, they have changed little for millions of years; the opossum’s relatives date back to 90 million years ago. However, the opossum didn’t appear in North America until about a million years ago. There are several species of opossums ranging from the size of a mouse to that of a housecat.
     Local common adult opossums are about the size of a large house cat, having a long, pointed snout with abundant teeth (50, the most of any North American mammal), small, dark eyes and rounded, bare ears. The tapering tail is naked and scaly, like a rat’s. Their feet have five toes, each with a claw, except the first toe of each hind foot, which is long and capable of grasping, like a thumb. They are excellent climbers, ascending hand-over-hand, using their prehensile tails for gripping and balancing. Their long, coarse body fur is light gray to white; outer hairs may be tipped yellow-brown or dark gray.
     Normally silent, it may growl, hiss or click its teeth when annoyed. They typically are not aggressive and usually freeze when frightened, giving them the appearance of being dead and leading to the old saying, “playing opossum.” When feigning death, an individual lies limp and motionless, usually on its side. Its eyes and mouth remain open, and its breathing becomes shallow. This state may last from a few minutes to several hours. Wildlife biologists have yet to determine whether feigning death is deliberate, a behavior evolved for survival, or involuntary, perhaps caused by nervous paralysis.
     Opossums are mostly nocturnal. Omnivorous and opportunistic, they aren’t picky about what they eat, eating all types of insects including cockroaches and beetles. Rats and mice are tasty treats, as are consuming dead animals of all types (carrion) and they think slugs and snails are a delicacy. Over-ripe fruit and human leftovers are also a favorite. One could call them Nature’s Little Sanitation Engineers; they help maintain a clean and healthy environment.
     Opossums are solitary, nomadic, (non-territorial). They seldom spend two successive nights in the same den. When food resources become depleted in one place, the animal simply moves to a new area. To discourage them from becoming a part-time resident, don’t leave pet food outside at night, keep ripe fruit picked, and keep garbage cans securely covered.
     Opossums may breed twice a year and give birth to as many as 12 young, to overcome the high mortality rate that most opossum populations face. An opossum is short-lived and has high mortality rates at all stages. Mortality of young still in the pouch ranges from 10 to 25 percent. Of those that survive through weaning, 6 to 9 youngsters, fewer than 10 percent live longer than one year. The oldest known wild opossums were 2 l/2 to 3 years old.
     Opossum predators include the wild, such as great horned owls, coyotes, humans, cars, dogs and cats.
     What to do if you encounter an Opossum… Nothing! Just watch and enjoy one of nature’s beneficial wild life species. If you must do something…try to imagine what it must be like to be an Opossum.