While commonly seen and often perceived as a pest, the Opossum (also called possum) is one of the more interesting, distinctive and benign animals we encounter. The Virginia Opossum (Didelphis virginiana), is the most common opossum species in North America.
General Description: The Opossum is light gray or black with a long, pointed snout and whitish face. Ears and feet are also generally black, with five pink toes extending from each foot. The long, scaly and hairless tail is largely prehensile, enabling the Opossum to hold onto tree branches. Opossum are great climbers. Their feet are 'hand-like', having 5 nimble 'fingers' on each foot. The thin, dexterous fingers help the Opossum grab onto branches, hold onto prey and even open up garbage containers! As you can see from their tracks, the rear track (below) closely resembles a human hand.
Of note, on the hind print of an Opossum, you will notice the 'thumb' has no claw. Due to the fact that claws generally don't register in Opossum tracks, this feature is often overlooked by trackers. Opossum feet are referred to as "plantigrade" - the means the Opossum walks of the soles of its feet with the heel touching the ground. Average Adult Virginia Opossum Length = 24" - 36" with tail Average Adult Virginia Opossum Weight = 5 - 12 pounds
Mating and Rearing: The Opossum is also the only marsupial in North America. The female has a pouch in their abdominal region where they carry and nurse their young, similar to Kangaroos, Koalas and Wombats in Australia. The mating season for Opossum is January through late summer. Opossum usually have 2 litters throughout the year and after a 13 day gestation period, a litter can yield anywhere from 7 - 15 babies. After birth, the baby is born hairless, blind and defenseless. The babies will crawl into the mother's abdominal pouch where they remain for two months. The mother has 13 nipples inside of her pouch which are used to nurse the babies. Should the litter exceed the number of nipples, some babies will not survive. Babies that do survive cling to a nipple for the entire time they are in the pouch. After emerging from their mother's pouch almost fully developed, they will be weaned at three months of age and after the weaning process, the mother will seek to mate again. Shortly after weaning, the baby Opossum will leave their mother and make their own way.
Infamous Defense Mechanism: Play Possum! The famous phrase is derived from the well known defense mechanism of an Opossum to play dead when threatened. The Opossum will lay on its side, breathing slowed and its tongue hanging out of its mouth. Predators will poke, nod and even bite the Opossum with no response. Since most animals will not eat prey that is already dead, the 'play dead' is quite effective. Scientists are sill unsure if this behavior is biologically or psychologically based. In other words, does the Opossum have some type of biological reaction to stress which forces it into a catatonic state? Or does the Opossum mentally recognize a threat and decide on their own accord to drop and play dead? It was initially thought that the Opossum must be in some type of temporary catatonic state, as it is able to slow its breathing down for hours. However, brain wave studies have been performed on 'play-dead' Opossum and the results show they are in a highly alert state when they are playing dead. In addition to playing dead, an Opossum will also secrete a foul smelling odor to ward of danger, as well as hiss at potential predators.
Diet and Behavior: The Opossum is an opportunist in all facets of life. It prefers a habitat of dense woods and thicket, but also thrives in urban environments. They make their den anywhere that is covered, dry and safe. They will use old dens of other animals, build their own, or even camp out in barns and attics.
The average range of an adult male Opossum is about .5 square miles (around 300 acres) while the female's range is about half that. Males are solitary creatures while females are generally surrounded by their young for most of the year. The Opossum is omnivorous, eating anything from small lizards, nuts and fruits to human garbage and road kill. The Opossum is crepuscular (active early mornings and late evenings) and is always on the look out for a meal. Opossum can store fat for future use and during the winter they can remain inactive for periods of 2-3 days in their dens. But because the Opossum does not store food or energy as well as well as racoons or bears, it must forage at all times of the year, even during periods of harsh winter.
Lifespan: The lifespan of an Opossum is very brief. In the wild, the average lifespan is 2-3 years and double that in captivity. Some believe the reason for such large litters is the high mortality rate of young Opossum, as well as the short lifespan in general. Large litters ensure some Opossum survive and in turn, the propagation of species.