Life With Tyrannosaurus Rex

So many extinct creatures . . . yet the lines of succession for genetic descendants are remarkable. Life on prehistoric earth was tough. Most everything was bigger, badder and creepier looking than it is today.  As repulsive as modern-day cockroaches are, they pale by comparison next to some of their nocturnal praying-mantis-like predatory ancestors. A number of different animal species survived the dinosaur extinction and some of them, in true cockroach fashion, evolved primordially hideous.  Take, for example, the modern-day Opossum. Opossum-like peradectids also lived during the dinosaur era and the modern version, at best, can only be described as butt-ugly. With a stubby awkward body, coarse stringy hair, a long pointy snout tipped with a cooked-ham-pink nose, an oversized grin that distorts the face and displays a rack of sharp teeth, little pebbles of eyes, black and insolent and a buck naked rat-like tail. . .well. . .this mammal defines grotesque.  The good news?  Just like 67 million years ago, Opossums still eat cockroaches like candy!

If you don’t spend much time in shadow and dark, chances are you’ve seldom seen an opossum in the flesh. They hardly ever show themselves in the daylight, except in colder northern climates. Like snakes and spiders, opossums make such poor first impressions that people often respond irrationally. When you add this to human ignorance and storytelling, the opossum’s reputation is tormented by endless fictions and myth. Here are a few: the idea that opossums hang upside down by their tail when sleeping, that they are autogenic carriers of rabies or that the male opossum mates through the female’s nostrils and she then sneezes her babies into her pouch.  Oh my. There ought to be a law that a mind requires a license-to-carry!

We’ll get to some of these fables later—but for now, what is an opossum? It’s a mammal to be sure, but it’s also a marsupial—in the Americas, the only marsupial found north of Mexico (there are others in South America).  This means it incubates its young in a pouch like a kangaroo or koala. It has a prehensile tail, “thumbs” on its feet and a bizarre routine of playing dead when threatened.  Opossums come in several dozen different species but in North America when you run into one it will be the Virginia Opossum (Didelphis virginiana—Dedelphis means double womb and refers to the pouch as a special incubator).  This particular species is believed to have migrated from South America after the Isthmus of Panama reconnected the two continents some 3 million years ago.  From such a primal lineage, the opossum is today a successful survivor with an increasing geographical range due to its unspecialized biology, flexible diet and reproductive methods. Let’s take a closer look.

Can you imagine how fortunate it is to eat things nobody else likes? It makes survival a whole bunch easier. One of nature’s top-line sanitation engineers, opossums are scavengers.  They’ll eat just about anything that’s dead, rotted or putrid, including contents of garbage cans and dumpsters. When forced to hunt for food, opossums will take mice, insects, worms, birds and even snakes.  Given the right circumstances, they’re also fond of eggs and cooped up chickens! Fruit, nuts and grass are on the cart-du-jour too.  Just not finicky.

Despite this squalid lifestyle, opossums are seemingly blessed with super powers. They have a whopping 50 teeth in that hungry mouth, more than any other land mammal in North America.  They aren’t Lyme disease carriers even though they love ticks—they eat and digest most of the ticks that are unfortunate enough to get on them! They also hardly ever contract rabies.  Fact is opossums are immune to a lot of stuff, to include the venom of rattlesnakes, cottonmouths and other pit vipers.  Still, you need to be careful . . . they can carry a slew of other diseases, such as leptospirosis, tularemia and tuberculosis to name a few. Just saying.

Though preferring to travel by land, opossums are also skilled swimmers and can use their opposable thumbs and long tails to efficiently climb. Myth-buster: while babies can temporarily hang from a branch by their tails, adults are too heavy to do this for very long. The tail is mostly used as a grip to carry bunches of leaves or bedding materials to the nest or as an extra limb when climbing. 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. When looking for a home, opossums tend toward streams, swamps and forests but can live almost anywhere, to include under your front porch. Tree forks, hollow logs and abandoned dens all make first-class domiciles.

Opossum nomenclature is also a bit odd. The slang name “possum” is an abused version of “opossum “from early American lore. Fact is, there are actual (smaller) tree-dwelling marsupial species found in Australia, New Zealand and China that are properly classified as possums. It gets better. In true marsupial fashion, baby opossums are called joeys. In famous nursery rhyme fashion, a male opossum is known as a Jack, the female is a Jill. In totally off-the-wall fashion, a group of adults is a passel . . . Jack and Jill are part of a proverbial passing passel of proudly prolific possums (okay, that’s enough abuse!).

An unexpected opossum encounter will stand out in most people’s memory. When threatened, opossums run, growl, belch, hiss, urinate and defecate. If protecting their young, add biting to the list.  When all else fails, the opossum will “play possum” and pretend to be dead. It flops over on its side like a sprayed insect, the body stiffens, the lips are drawn back, teeth are bared, saliva forms around the mouth and its eyes either close or stare off blankly into space.  Clearly, this is a dead animal!  The coupe-de-grace is a foul-smelling secretion from the anal glands.  Looks dead, smells dead . . . must be dead—or at least that’s what the opossum hopes.  No self-respecting fox or bobcat wants to eat a dead opossum! Even more bizarre, this is NOT an act; it’s an involuntary physiological reaction, like fainting from fright, rather than an attempt to outwit a predator. If you come upon what appears to be a dead opossum, it’s best to leave it in a quiet place with a clear exit path.  In time, the opossum will probably “come to” and boogie out of Dodge.

Also on the “strange” list is the opossum’s unusual reproductive processes—it has fascinated folks for a long time. First, let’s debunk the myth of nasal sex. Even though it could pass for an “alternative fact” in today’s wingnut socio/political environment, this falsehood is derived from the biological oddity of bifurcated sex organs (a common marsupial trait).  That’s right, the male opossum has a two-pronged penis and the female has a double vagina!  As kinky as it might be, nasal sex is not required; they fit together just fine . . . (ahem).

As a marsupial, the young complete most of their development inside their mother’s pouch after birth, instead of in a placenta over a long gestation period like most mammals. This way mothers don’t have to spend much time and energy with a long pregnancy. That’s because things happen fast in the hood. Gestation is just shy of 2 weeks; the honey-bee-sized joeys (basically embryos at birth) crawl into the pouch where they latch onto a nipple for the next 50-70 days. Sad fact: momma has 13 teats; any more babies than that will clearly not survive. Nature can be cruel sometimes.

When babies become too large to remain in the pouch, they climb onto the mother’s back and are carried there as she searches for food—this makes for a strikingly bizarre sight. At this time the young are learning survival skills such as finding food sources and predator avoidance. Everything’s on a fast track. The rapidly growing joeys stay with their mother for only 100 days. They become sexually mature at 6-8 months because life is short.  Opossums live for only 2-4 years.

The breeding season for the Virginia opossum can begin as early as December and continue through October with most joeys born between February and June.   The female can have 1-3 litters per year. Most communication functions are based on “clicks.” During the mating season, Jack hooks up with Jill by making clicking sounds with his mouth and Jill will use similar clicking sounds to round up wayward joeys who get separated.

In summation, what can we say about these somewhat strange and disconcerting critters? Ugly, strange, different? Yes, but be sure to give them respect.  They were among the one quarter of plant and animal species on Earth to survive the big extinction event. Unlike us, they once shared the planet with Tyrannosaurus Rex.

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