Nature Notes: Virginia Opossum
Most of us have a weak spot for a particular wild creature, one that appeals to us as beautiful, cuddly or endangered. For me it is the Rocky Mountain elk, one of North America’s most impressive mammals. Other people might favor the common loon, a baby bear, or the grey wolf. But some folks become attached to animals that are neither very attractive, nor particularly friendly to humans. Let’s put the tarantula in this category, and I won’t be buying a python. It seems that for many people, the lowly opossum falls into this category.
Don’t believe me? If you search online you will find there is an Opossum Society of America. Or you could join the distinctive National Opossum Society for $25 per year. There is also a group called Opossum Awareness and Advocacy with over 133,000 Facebook friends, possibly one friend for every opossum north of the Mason Dixon Line. I even found websites where you can purchase opossum snacks like wax worms, grasshoppers, caterpillars, coconut, papaya and mango! So what is the attraction of this unique little fellow?
I don’t want to offend any of you fans out there, but the opossum won’t win many beauty contests. It has a long, conical head with black eyes, light colored hair, a big pink nose and round ears like Mickey Mouse. The gaping mouth contains 50 sharp, pointed teeth. The body of 18 to 24 inches is covered in sparse fur ranging from black to grey, followed by a round, scaly, 12-inch tail. The animal has a distinctive walk more accurately called ambling, and a top speed of only seven miles per hour when trying to cover ground quickly.
But when we look more closely at Didelphis virginiansus we find a number of special attributes that distinguish it from most North American animals. First, it is the only marsupial on our continent, a cousin of the kangaroo, koala and wombat in Australia. Marsupials have dual wombs and a special pouch called a marsupium for rearing their helpless young.
That tail comes in handy for balance, while climbing or carrying nesting materials, and can be used for hanging from a limb. Their hind feet have opposing toes that allow the opossum to grip, much as humans do with our thumbs.
Opossums have a long history on Earth, with fossil records of early forms of the animal dated to the Cretaceous era, over 65 million years ago. They seem to have originated in South America, but migrated north through Latin America when the continents shifted and connected. Ever since, opossums have been expanding their territory, reaching New England in the 1900s and beginning to appear in numbers here in Maine within the 21st century.
Scientists rate the opossum as poorly suited to survive long, cold winters in Maine but climate change and the adaptive skills of the animal have allowed them to hold a place in our animal kingdom.
The first references to the animal in print date back to 1610 when John Smith and others began to write about the “aposoum” or “opassom” from the Algonquin/ Powhatan words for a “white dog-like beast.” At that time William Strachey noted that the creature was similar in size and taste to a pig. To this day, in some southern cultures the opossum is valued as table fare, often roasted and served with sweet potatoes. President Jimmy Carter was known to have hunted them for food. They are legal game animals here in Maine, and may be hunted or trapped during open seasons, but their fur has little value.
Opossums are generally nocturnal, solitary hunters, subsisting on carrion, insects, fruits, nuts, slugs, snails, snakes, frogs and rodents. The carrion habit puts opossums on the road at night, and often results in opossums becoming road kill themselves. Given the chance, they will raid your orchard, chicken coop, bird feeder or household garbage and they will filch any pet food you leave outdoors. Seeking food and warmth, opossums are happy to enter homes through unsecured pet doors, often triggering calls to animal control specialists to remove them.
In the wild, opossums favor hollow trees, rotten logs or abandoned ground dens for habitation. They move regularly to avoid predators zeroing in on their location. Human development offers opossums other choices for living near food and warmth, and they will happily take up residence under porches, in barns and under wood piles. They will gather grass and leaves to line their nests for additional warmth during cold spells.
Breeding season runs from January into the summer, and opossums are capable of delivering two litters each year. As many as 17 pups have been reported in a litter. The gestation period is short, only 11 to 13 days before the tiny babies leave the womb and crawl into the marsupial pouch. Here they must attach to a teat to obtain nourishing milk that will sustain them for another three to four months. The pouch closes so tight that the mother can swim without the pups getting wet.
After weaning the pups will ride on their mother’s back, hanging tight to her hair with their feet and tails. Soon the pups disperse to find their own territories so the female can deliver another brood. This active breeding is necessary since only 10 percent of pups are estimated to survive one year, and most opossums are dead within two to three years.
When threatened, opossums are not aggressive, even though their sharp teeth, hissing and growling may scare off some predators. They have a unique survival mechanism often referred to as “playing possum.” This involuntary catatonic state results in the animals flopping on their sides with an open mouth dripping saliva or foam, and the spontaneous release of a strong odor from scent glands at the base of their tail. While in this state, the opossum can be poked and prodded, even picked up without revival. Some predators, like dogs and foxes that don’t eat carrion, may be fooled by this tactic, leaving the opossum alone to recover in a few minutes or a couple hours.
Coyotes, raccoons, bobcats and raptors are all known to take opossums for food. Interestingly, opossums are immune to most snake venoms, something that has been studied by scientists hoping to find effective antivenoms.
Opossums should be handled with caution because they can give a serious bite if provoked. On rare occasions they have been documented as carrying the rabies virus. Some research has shown they can carry the parasite that causes equine protozoal myeloencephalitis, a disease of the horse central nervous system.
There is one redeeming feature of opossums that may endear them to hikers and gardeners: the fact that they will consume ticks. Along with chickens, egrets, turkeys and guinea fowl, the opossum seems happy to snack on any ticks they find. The Cary Institute of Ecosystem Studies reported that due to their short legs and long belly fur, opossums pick up ticks along the ground and are estimated to consume up to 5,000 ticks annually. It might take a lot of opossums to make a dent in our dastardly deer tick population, but it appears the opossum is here to stay!
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