The opossum is about the size of a cat with gray and black fur, dark eyes and ears, pink nose and feet and a furless tail.

They are North America’s only marsupial which means the females have a pouch. When young opossums are born (13 days after conception), they are not fully developed and are about the size of a pinky fingernail.

They must fight, crawl and inch their way to the pouch (marsupium). From that point It’s nature’s version of musical chairs.

There are 13-15 teats and the young that get there first have a pretty good chance of surviving. The average litter is 8-10 young and the female can have up to three litters a year.

The young stay in the pouch and nurse for about 3 months before venturing out into the big world. They cling to mom and ride around on her like a furry taxi.

Because she has so many young and she can’t count, she might not know if one of the young slips off. When we get calls about a young opossum all alone, we ask the caller to bring it to us because the mother won’t be back.

A good animal

Some think opossums are dirty and are hosts to many diseases when just the opposite is true.

Due to an opossum’s low body temperature and successful immune system, it’s very rare for one to carry rabies. Opossums are extremely clean because they groom constantly.

Opossums follow their noses and will eat almost anything including cockroaches, crickets, beetles, slugs, snails, rats, mice and fruit. And, would you believe ticks? Because they are good at finding ticks and can kill about 5,000 ticks in one year.

Several years ago, biologists from the Cary Institute put opossums and other species, like chipmunks, squirrels, mice and catbirds to the test, giving each animal 100 ticks to eat.

Opossums killed and ate far more ticks than any other animal.

They were more successful than the others at remembering how to find the ticks as they wandered through a maze.

Don’t be frightened

Scared opossums may hiss, growl and even bite if cornered. They have 50 teeth — more than any other mammal, so if threatened they could deliver a pretty good bite.

It is much more likely that the opossum will “play dead” when confronted. This reaction is involuntary and automatic and can last anywhere from 40 minutes to four hours.

The opossum’s body becomes limp, its front feet form tight balls, its lips are drawn back, and drool runs from its mouth. They will secrete a foul-smelling substance to smell dead.

Opossums are extremely adaptable and live in a variety of habitats and climates. The most important needs for the opossum’s home range are food, water and shelter.

Opossums will take shelter in abandoned burrows, hollow logs, brush piles, woodpiles, attics and other man-made structures.

Historical creatures

They’ve been around longer than any other mammal.

Opossums are often called “living fossils” because they’ve been able to survive on our planet for millions of years — over 70 million, to be exact. They are skilled climbers, thanks to their opposable rear thumbs and long tails. They are good swimmers, although they prefer to travel on land.

Our educational opossum, “Elvis” opened his cage one night and wandered about the center raiding trash cans.

As I cleaned up his messes, I noticed he had eaten almost an entire begonia plant. This house plant is toxic to cats and dogs, but I didn’t know if this was true for opossums.

I found an article in the Journal of Venomous & Poisonous Animals and Plant Toxins outlining researchers’ work on isolating a protein known as Lethal Toxin-Neutralizing Factor.

The LTNF protein is exactly what it sounds like; a protein that seeks out otherwise lethal poisons, toxins and venoms and neutralizes them. Whew!

Opossums have this protein, so we did not have to worry. I don’t know if the begonia gave him heartburn or not, but thanks to this protein, that was the worst thing that could have happened.

Growing up, I was always told … “Don’t judge a book by its cover.”

I think that can be said for opossums. There is so much more to learn about these creatures if we can just get past their “covers.”

Jeannie Carl is a naturalist at the Carbon County Environmental Education Center in Summit Hill. The center rehabilitates injured animals and educates the public on a variety of wildlife found in the area. For information on the Carbon County Environmental Center, visit www.carboneec.org.