Blane Klemek: Are Opossums on the move north?
BEMIDJI — I have yet to observe a wild, living Virginia opossum. And even though Minnesota is home to one of North America’s most unique and unusual mammals, observing one in the Northland is practically nonexistent. Or is it?
While it is exceedingly rare to observe one of these creatures in our neck of the woods, the strange looking animals are observed with increasing regularity throughout the north-central part of the state. Most opossums, however, inhabit woodlands throughout southern Minnesota.
The first time I became aware I was in ’possum country, was several years ago when I assisted fellow wildlife biologists of the Mississippi Flyway with a scaup banding project near Keokuk, Iowa. Taking a drive one evening to enjoy the countryside in the Mississippi River valley along the Iowa and Illinois border, I observed from time to time dead opossums on the roadways.
About the size of a house cat and around 3-feet long from the tip of its pink nose to the tip of its naked tail, the Virginia opossum, which resembles an overgrown rat in some ways, is far removed from a rat in many more ways. In fact, unlike any North American mammal, the Virginia opossum is the only marsupial in the entire continent.
Marsupials are typically associated with Australia, such as kangaroos, wombats, and koala bears. In fact, 140 species of marsupials are found in Australia. Moreover, while most of Australia’s marsupials are found nowhere else in the world, it is ironic to note that marsupials evolved first in North America (odd, then, that we’re left with only one).
Like all mammals, marsupials, including our North American marsupial, possess a hairy covering and suckle their young from mammary glands that produce nutritious milk. However, what they do have that no other mammal has (although even among marsupials there are exceptions to even this trait), is a “marsupium”, or pouch as it commonly called. Most marsupials have permanent pouches, but there are a few that have temporary pouches and some that have none at all.
Okay, so what’s a pouch for? First off — yet not unique among mammals — all marsupials give birth to live young. What is unique is that the gestation period of marsupials, including opossums, is very short, resulting in the births of undeveloped, helpless, hairless and completely blind youngsters.
The tiny newborns have surprisingly well-developed forelimbs with strong claws that enable the youngsters to cling to their mother’s belly fur and crawl to the safety of the protective pouch. Once inside the warm and snug pouch, the offspring locate a teat and attach themselves, begin suckling and continue their development. The whole ordeal, from birth to pouch, is completed with no help from mother opossum whatsoever.
The security of their mother’s pouch is such that for another month’s time, the baby opossums are in and out and rarely go very far. When they are about the size of mice, opossum babies begin spending most of their time hitching rides on their mother’s back until becoming more independent and eventually leaving all together.
Virginia opossums are covered in grayish fur everywhere except for its feet, tail, and ears. The nakedness of these body parts might lend credence to why the animals are not often seen farther north. Nonetheless, the assumed shortcomings haven’t stopped the non-hibernating opossums to taking up residence in Minnesota.
Other anatomically unique features of the opossum is its tail and “thumbs.” The tail is essentially another limb, “prehensile” as it is called, and able to wrap around and grasp limbs as an adaptation for climbing. The thumbs, or “halluxes,” are indeed opposable just like our own thumbs. Though located only on the rear feet, an opossum’s halluxes enable the animals to securely grasp branches as they maneuver up and down trees.
Perhaps one of the most interesting opossum behaviors is what it will do when threatened or frightened. Purely a survival mechanism, opossums are masters at fooling would-be predators into thinking that they’re dead. It’s of course where the expression, “playing ’possum” originally came from.
Virginia opossums will frequently roll over, stiffen, salivate, and breathe ever so slowly and shallow in a coma-like state that can last as long as four hours. Such behavior often confuses predators that are accustomed to running and escaping prey. Thus, some potential predators give up and leave.
The Virginia opossum, a strange but very interesting mammal, seems to be finding new niches in Minnesota. For example, my brother-in-law who resides in Glenwood, recently discovered a dead opossum along a roadway near Villard. And after I began talking with trappers in the Alexandria-Glenwood area recently, these trappers and others have been routinely catching opossums for many years now.
As such, and as the years continue to pass, I believe that it’s only a matter of time that opossums begin showing up here in the Northland as we get out and enjoy the great outdoors.
BLANE KLEMEK is a Minnesota DNR wildlife manager. He can be reached at firstname.lastname@example.org