North American Opossum in Winter

Untouched color-colour photograph by J. McCombie.
We first saw this Opossum on the last evening of fall before the snow fell. Then, as winter turned to spring, he emerged to enjoy the change of seasons. It was just around 1:00 p.m. when I discovered him dining on pieces of bread I had laid out for the birds on our back porch. Fifteen minutes later, when he had enough of that, he wandered around the deck for a while and leisurely strolled to the front of the house and sauntered down the stairs to investigate what was below the snowball bush. After that, he meandered his way across the lawn to beneath the apple and crab apple trees to forage the seeds and nuts which had fallen as the birds feed from their feeders. He spent a great deal of time there and I followed him around. He didn't seem to notice me for an hour, but once he put his nose up in the air and determined my presence, he slowly made his way up the tree. He sat there quietly looking at me, so I left him alone. Just a few minutes later, he disembarked from the tree and was back to feeding under it. He spent the rest of the day into the evening there and returned the next evening.
The Possum or Virginia Opossum is not native to Southern Ontario, but arrived several decades ago from the USA and appears to be breeding successfully.
The opossums, also known by their scientific name Didelphimorphia, make up the largest order of marsupials in the Western Hemisphere, including 103 or more species in 19 genera. But it is the only North American marsupial. They are also commonly called possums, particularly in the southern United States, although that term also refers to Australian animals of the suborder Phalangeriformes. However, the Opossum of North America is a different species than it's Australian cousin. The Virginia opossum was the first animal named an opossum; usage of the name was published in 1610. The word opossum was borrowed from the Virginia Algonquian (Powhatan) language in the form aposoum and ultimately derives from the Proto-Algonquian word *wa˙p- aʔθemw, meaning "white dog" or "white beast-animal".
Their unspecialized biology, flexible diet, and reproductive habits make them successful colonizers and survivors in diverse locations and conditions.
Most members of this taxon have long snouts, a narrow braincase, and a prominent sagittal crest. By mammalian standards, this is an unusually full jaw. The incisors are very small, the canines large, and the molars are tricuspid.
Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. Some families will group together in ready-made burrows or even under houses. Though they will temporarily occupy abandoned burrows, they do not dig or put much effort into building their own. As nocturnal animals, they favor dark, secure areas. These areas may be below ground or above.
Although they prefer to avoid confrontation, these gentle, placid little creatures will hiss, growl and show their teeth when cornered! If alarmed, threatened or harmed and unable to escape, the possum may fall into a state of shock and unconsciousness, and may appear to be dead, hence the term "Playing Possum", mimicking the appearance and smell of a sick or dead animal. This physiological response is involuntary (like fainting), rather than a conscious act. In the case of baby opossums, however, the brain does not always react this way at the appropriate moment, and therefore they often fail to "play dead" when threatened. When an opossum is "playing possum", the animal's lips are drawn back, the teeth are bared, saliva foams around the mouth, the eyes close or half-close, and a foul-smelling fluid is secreted from the anal glands. The stiff, curled form can be prodded, turned over, and even carried away without reaction. The animal will typically regain consciousness after a period of between 40 minutes and 4 hours, a process that begins with slight twitching of the ears. Threatened opossums (especially males) will growl deeply, raising their pitch as the threat becomes more urgent. Males make a clicking "smack" noise out of the side of their mouths as they wander in search of a mate, and females will sometimes repeat the sound in return. When separated or distressed, baby opossums will make a sneezing noise to signal their mother. If threatened, the baby will open its mouth and quietly hiss until the threat is gone.
Adults are about the size of an average house cat to a small mouse and are solitary, nocturnal and gray in colour, although their coat appears to change colour with it's surroundings. Adult opossums do not hang from trees by their tails, as sometimes depicted, though babies may dangle temporarily. Their semi-prehensile tails are not strong enough to support a mature adult's weight. Instead, the opossum uses its tail as a brace and a fifth limb when climbing. The tail is occasionally used as a grip to carry bunches of leaves or bedding materials to the nest. A mother will sometimes carry her young upon her back, where they will cling tightly even when she is climbing or running.
Opossums are small to medium-sized marsupials which means that they give birth to babies at a very early stage of development. At birth, these little critters are about the size of a Kidney Bean! Litter size can be up to 13 babies. They are then carried around on the mother's back for another 1 - 2 months. The young then crawl to the mother's pouch and latch onto a nipple, where they stay and feed for about 2-3 months, until they emerge from the pouch to face the outside world. Here in Southern Ontario these little creatures are mostly seen at night, as they check out the garbage cans for dinner, or at the side of the road, dead. They have adapted to living with people in the countryside and in small towns, but have not adapted to the presence of fast moving cars. Sadly, hundreds of them are killed each year on roads and highways. In the past few decades, it seems that some poor unsuspecting Opossums have taken a nap on a stationary train or truck somewhere in the Southern States, and woken up to find themselves in Canada, with no way for them to get back. These reluctant little immigrants settle in, breed and manage quite well in their first summer here, but when the cold winter arrives things get tough for these little marsupials. They are not well adapted for cold northern winters in Southern Ontario so some animals have bits of their ears and tails missing, due to frost-bite.
They are true semi-arboreal omnivores and will eat insects, snails, rodents, berries, fruit, grass and leaves, eggs and vegetables. They suffer predation by dogs, cats, Hawks, and Owls, and of course, humans (and cars).
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