Possums – Odd and Ancient (Part 1 of 2)

  • Possums are Marsupial’s
  • Possums Play Dead to Live
  • Possums have More Teeth than Any Other Mammal
Possums are 70-million-year-old survivors from the time of dinosaurs and have none of the normal qualifications for survival, making them a bit different in the world of wildlife.
Possums are commonly thought by scientists and wildlife biologists to be 70-million-year old survivors from the time of dinosaurs and have none of the normal qualifications for survival, making them a bit different in the world of wildlife.

By Jill J. Easton

Possums are weird.  These 70-million-year-old survivors from the time of dinosaurs have none of the normal qualifications for survival.  They are slow and empty-headed, their main trick is to play dead.  Almost nothing will eat possum, especially one that looks and acts long-dead.  But more about that later.

Possums are not one of the major predators of ground-nesting birds, but they will eat eggs, chicks and anything else that comes within their limited hunting range.  Next to hogs they are probably the largest producer of hungry offspring.

First the Facts

The Virginia Opossum, Didelphis Virginiana is the only marsupial found in the United States.  Marsupials are mammals that raise their young in pouches that provide protection and milk to the babies.  Other marsupials are animals like the kangaroo and koala, both found in Australia.

Possums have to have been designed from spare parts.  An adult’s head looks too big for its body, the back feet should belong to a monkey and the tail to a giant rat.  The opossum has 50 teeth, more than any North American land mammal, and a lower body temperature as well.  Its hairless tail is prehensile to grasp branches and is also used for balance.  Contrary to folklore, only young possums hang upside down by their tails.  The opossum has opposable thumbs on its hind feet which they use for holding on to branches.  Possums also have one of the smallest brains for their body size of any mammal, this makes them hard to kill.

In the past 100 years, possums have hugely extended their range.  They originally were animals of the south, but now possums have been found so far north that they are commonly found with their tails and ear tips frozen off.

Possum Sex Isn’t Simple

For many years, country folks thought female possums had sex through their noses.  When mama grinner was ready to give birth, she supposedly sneezed the babies into her pouch.  This isn’t exactly what happens.

The true story is a male possum has a bifurcated, or split, penis.  It is Y shaped with two separate sperm delivery heads.  Country naturalists assumed that since the male had a double it had to go into a double opening.  The only visible place on a female possum that was double was her nose.

The reality is just as odd.  The female possum actually has two separate sets of baby-producing equipment that branch out internally to match up with the two-pronged penis.  So mom produces two different sets of babies at birth.

And Then They Are Born

Marsupials birth their babies after a gestation period shorter than some first dates.  The babies are pushed out of the womb 11 to 14 days after the eggs are fertilized.  The preemie-possums are smaller than dried peas and twenty or more can fit on a teaspoon.

To survive, the tiny, blind, naked infants have to make a perilous journey under the mother’s tail, fight through the hair on her belly and squirm into her pouch.  Many fall off and die along the way.  Imagine climbing Mount Everest by wiggling along on your stomach with no clothes and not able to see or hear.  The possums who survive the epic journey still have to fight for milk since the teats in the mom’s pouch can only support 13 of the 20 plus babies that are usually born.

A week after their journey into the pouch the babies have tripled in size, at about 70 days their eyes open and a few weeks later the pouch reaches overflow stage.  Now the young opossums each weigh about an ounce and are the size of a deer mouse.  After being crowed out the babies climb up mom’s back and ride with their tiny prehensile tails wrapped around her fur.  For the next month mom teaches them to find food by digging grubs and worms and consuming almost anything vaguely edible, animal or vegetable.  After about a hundred days the young possums wander off to lead their own, mostly solitary, lives.

Now Let’s See, To Survive, They Die?

Opossums have one of the least practical modern survival mechanisms in the animal world; they play dead.  This might have worked well when being threatened by a velociraptor 70 million years ago, but it fails miserably when used against a pickup truck.

Possums do something similar to fainting.  The possum assumes the ‘grinner position’ flat on its side with lips pulled back to expose clenched teeth, often a foam of saliva drips out of the mouth.  On the other end a foul-smelling fluid leaks out the anal glands.  This discourages canines and other meat eating animals, but it makes possum’s easy targets for buzzards, eagles and bird predators who relish a temporarily immobile animal.

Some grinners can be prodded, turned over and even carried away without reacting.  Sometimes it takes as long as four hours for the animal to return to normal.  The awakening process begins with slight twitching of its ears.

Part 2 – Next Week – Trapping, How Not to Catch a Possum