So before we begin, let me correct one misconception. The Opossum is, in fact, a marsupial, meaning it carries its young in a pouch on its body, until they reach full development and can venture out on their own. It is not at all related to the “possums” of Australia or New Zealand. These foreigners are correctly called “possums”, while ours has an “O” at the start of its name. The word Opossum originates from the Proto-Algonquian aposoum, meaning "white dog" or "white beast. The Australian possums are cute, furry and have thick bushy tails, in contrast to our “ugly” Opossum. Well, there is one other similarity, both are omnivores, meaning they will eat almost anything. Food is variable and can include, fruit, vegetables, carrion, bones and almost anything else edible.
The Virginia Opossum is the only marsupial in North America, but has 102 relatives throughout Central and South America. All are similar in behaviour but some look very different in structure and size. Most are nocturnal or crepuscular, meaning they hunt at dawn, dusk and during the night. Most also have many large, sharp teeth for defense and feeding. One feature that helps with their partially arboreal lifestyle is the opposable, clawless “thumb” on their hind feet that allows them to grip branches and slippery surfaces. Add to this, their prehensile tail, and they truly do very well in the trees.
Many young are borne, but few survive, as the early days are very difficult for them. The young are born, after a 12-14 day gestation period, as poorly developed animals, due to the female’s under-developed placenta. Their success relies on the baby being able to quickly find the female’s marsupium (pouch), climb inside and latch onto the female’s teat. If they don’t find the teat quickly they will die in hours. They are finally weaned between 70 and 125 days later and only then can they leave the pouch.
Remarkably, Opossums exhibit partial or total immunity to the venom of many snakes, including rattlesnakes, cottonmouths and other pit vipers. There are lots of predators out there and everything from foxes, owls, hawks and coyotes are happy to munch on them. The Virginia Opossum is a medium-sized animal that can be very intimidating, with its open mouth, snarling posture and copious teeth, but really, its best defense is to fake death!
Known scientifically as thanatosis, playing dead is a defense mechanism utilized by many animals, from ants, to ‘fainting’ goats, some birds, sharks, many other species of fish, stingrays, iguanas, anoles (a small lizard), snakes, and spiders. The phenomena are a response to stress-induced fear, where the animal essentially feigns death as its respiration and heart rate drop to the point that they appear to be lifeless. Ironically they become paralyzed during these periods and couldn’t flee if they wanted to.
When the threat has passed, the normal functions resume, and the animals toddle off as if nothing was wrong! But isn’t this dangerous? Well yes, because they become essentially helpless. But most predators hunt by instinct and their flight and pursue stimulus is strong. So if a ‘dead’ animal is encountered, they tend to move on (unless they are scavengers of course). Humans have even been known to employ this defence, as well. Seems a bit risky, but there’s lots of Opossums around so it must work!
The Opossum is marching ever northward and, although not seen very often, is actually quite common in Durham Region. I saw one the other night in Scugog Township and have had them in my yard several times. They are a hardy animal, albeit not pretty to look at, but serve an important purpose in our local environment, as do all scavengers and predators.
Geoff Carpentier is a published author, ecotour guide and environmental consultant. Visit Geoff on-line, at www.avocetnatureservices.com, and on LinkedIn and Facebook.