Feature Article
The Awesome Opossum
By Cathy Case
Jun 13, 2008, 23:08

Photo by Marcia Rybak

One of the most misunderstood inhabitants of our cities and backyards is the Virginia Opossum (didelphis virginiana). This amazing creature is North America’s only marsupial – an animal that rears its young in a pouch. They are found all over the U.S. except in the coldest regions and because they’re nocturnal, most people never see them as they quietly go about their nighttime business of cleaning up the environment.

Mother Nature has endowed the opossum with 50 teeth, more than any other mammal, and although it will growl, hiss, drool, and show you all of those fearsome looking toothy protrusions if it’s cornered or frightened, they are not generally aggressive and prefer to flee rather than fight. The opossum’s natural defense against predators includes the display of those alligator like teeth and the ability to emit a foul smelling discharge from the opposite end, and if that still doesn’t deter the attacker, they can involuntarily fall into a catatonic state, the famous “playing possum!” Since most predators prefer not to eat smelly, dead prey, these natural defenses sometimes allow the opossum to elude its most common natural predators—coyotes, hawks, and foxes.

Opossums are attracted to an easy meal of road kill, indulging its preference for food other animals turn down. Unfortunately, feigning death in the street in front of an oncoming automobile is not the ideal mode of defense, and thus, most opossums fall victim to vehicles.  Many others are injured or killed by territorial dogs defending their yards.

What should you do if your dogs have a nighttime encounter with an opossum in your yard? Just bring the dogs indoors for an hour or two. The opossum will exit the yard as soon possible since it was just passing through, looking for a meal of snails, slugs, mice, rats, dropped fruit, worms, or insects and was thoroughly terrified by the dogs.

Opossums are known as terrestrial gleaners, in constant movement searching for food as they meander along on their nocturnal journey. They do not have territories and rarely stay in the same location for more than a day or two. Only when one is observed wandering about during daylight hours should you be concerned. It may be ill or injured and you should call your local animal control for assistance. Opossums very rarely get rabies, but like all mammals, may harbor fleas and other parasites that can carry disease.

The opossum has been referred to as “Nature’s Sanitation Engineer” because of its dietary habit of cleaning up the environment of carrion and garbage. They prefer to eat fallen ground fruit and overripe vegetation, rarely climbing into trees to disturb fruit. Many people mistakenly think opossums are responsible for taking a bite out of hanging fruit, when the likely culprits may be tree or roof rats, which are also nocturnal and are coincidentally on the opossum’s menu!   Opossum feet have opposable thumbs, they do not dig, and cannot hang by their tails. The tail is used for stabilization and grasping branches.

Contrary to prevailing opinion, the opossum can actually reach speeds of up to 7 mph. Mother opossums with a cumbersome pouch full of babies are vulnerable to speeding cars and predators because they cannot move agilely or quickly. It is often possible for wildlife rehabilitators to rescue babies from a deceased mother’s pouch and successfully raise them until they can be released back into the environment. Therefore, if you see an opossum struck and killed by a car and can see babies in the pouch, they should be brought to a wildlife rehabilitator quickly for care.

When the babies are about four to five inches long (not including tail) they may begin hanging on to the Mother’s back as she moves from place to place in her nightly search for food. Any baby opossum found alone at this size must be brought to a wildlife rehabilitator for care because the mother will not retrieve lost babies, and the baby cannot survive on its own until it is approximately 8 inches long.

There are some steps you can take to make your backyard less hospitable to wildlife, including opossums. Bring in pet food and water dishes at night. Clean up brush and woodpiles that attract rodents, and cover trashcans. Pick up fallen fruit and remove overripe vegetables from the garden. Installing motion sensor lights will frighten nighttime visitors. Trapping is a poor option to deter wildlife. Since most nocturnal wildlife is not territorial, traps merely catch the wild wanderer looking for a meal on that night. Opossums severely injure themselves attempting to escape from traps. Every year, many adult opossums are illegally trapped, injured, and killed by humans who do not understand the important and beneficial role they play in our ecosystem – the awesome opossum is Mother Nature’s little sanitation department!

Cathy Case founded Shadow Oaks Wildlife Care, an all volunteer organization based in Thousand Oaks and licensed by the California Department of Fish and Game. The highly trained and experienced wildlife rehabilitators care for orphaned and injured small mammals from the West Valley to Southern Ventura Co. and work to educate the public how to coexist with native wildlife. For more information, please contact Cathy at (805) 374-9027.