Omnipresent opossum
Pleasant 'possum pouches protect perky progeny
By Callan Bentley
Flat Hat Variety Editor
It was one of those warm, calm late summer evenings that make people sip iced tea on the black porch and try and forget for a moment that they're due back at college next week. It was a time that seemed to have been expressly made just for relaxation. I wasn't sipping tea, though, but I was relaxing in my own way…
I was perched on my roof, peering down through binoculars into the stump of a cedar tree in my back yard. The cedar was old and hollow in parts, and an opossum was sleeping in one hollow nook, about fifteen feet above the ground. I watched the opossum roll over, yawn, stare up at me, and then finally amble out of the tree to begin its nightly rounds. After several hours of watching, it was too dark to see, and I was forced to abandon my observation. I wished for a pair of night vision goggles so that I could watch this fascinating animal engage in some more active behavior.
The Virginia opossum (Didelphis virginiana) is the only native marsupial on the continent of North America. Every other mammal you encounter from here to Alaska will belong to the orders of placental mammals. They are so named because of their placentae, organs that connect a developing embryo with its mother's uterus. Lacking this special connection, the opossum has some of the most intriguing reproductive habits of any critter on the continent.
Only 13 days after the fertilization of the opossum's eggs, up to 25 worm-like embryos are "born." Each is about the size of a navy bean. The tiny pink babies must crawl hand over hand to their mother's pouch, a marathon distance of about six centimeters. They have only instinct to guide them. Once in the pouch, the young opossums will attach themselves to one of 13 teats where they will suckle milk and continue their development over the next 100 days. Many will become lost along the way, and even if they do make it all the way to the pouch, extras will perish after discovering that there are no teats left.
After being weaned from the pouch, the immature opossums will cling to their mother's back fur until independence at the age of three or four months. The females are full adults at six months, and males reach their full virility after about eight and a half months.
The adult opossum is about the size of a large house cat. It has grizzled white fur on top, and black-tipped fur below. Its ears and tail are hairless, often pink in color, sometimes tinged with black. Its legs are short, and the first toe of the hind feet is opposable, allowing the opossum the use of four thumbs in total. Similarly, the tail is regarded as prehensile. Though myth depicts the opossum as able to hang from a tree branch by winding its tail around it, the truth is that the tail is nowhere near strong enough for such a stunt. It is mainly used for balance and for hauling leaves back to the nest.
The opossum has one of the most varied diets of any local animal, eating a greater variety of foodstuffs than even the raccoon. Known opossum meals include insects, earthworms, berries, nuts, acorns, corn, mice, small rabbits, frogs, carrion from road kill, and snakes (including many poisonous species to whose venom the opossum shows an extraordinary resistance). Cannibalism is not unusual. In fact, many opossums are killed along America's highways as they attempt to dine on their late relatives.
The opossum, being marsupial, does not hibernate, and so it is possible to encounter one in the winter in Williamsburg. It is a nocturnal animal, and students are most likely to encounter it ambling along dark wooded roads or raiding College trash depots.
If you do encounter an opossum, be careful. Though the animal is probably more interested in getting away from you than anything else, it is a wild creature and therefore unpredictable. Add to this the opossum's small brain size, reputation for a grumpy disposition, ability to contract rabies, and the 50 teeth lining its gums, and you get a picture of an animal that you shouldn't mess with.
If you do, for some twisted reason, attempt to disturb the opossum, you may be in for a surprise. The opossum reacts to stress in an unusual way: when attacked or molested, the animal goes into a shock coma, appearing as if it were dead. This "playing 'possum" is made complete by a lolling tongue and the animal's habit of defecating and secreting a foul-smelling greenish substance from its anal glands. Often, this bizarre display is enough to drive off any predator thinking of making a meal of the opossum. What looked like a nice fresh meal now stinks as if it's been dead for several weeks. This display is relied on to be effective, and it must be. The opossum is truly comatose, and cannot defend itself until it wakes up again.
When it comes to, the opossum
will look around cautiously and go back about its business. While many mammals
are sleeping the winter away, the area's opossums are scurrying about, working
just as hard as Flat Hat natural history reporters.