The Virginia opossum ( Didelphis virginiana) is North America's only marsupial, a unique mammal known for its adaptability and scavenging habits. Often misunderstood, opossums play a significant role in various ecosystems. This article delves into the opossum diet, its impact on the environment, and how to coexist with these fascinating creatures.
Opossums: North America's Only Marsupial
Opossums belong to the order Didelphimorphia, the largest group of marsupials in the Western Hemisphere, comprising 126 species in 18 genera. The Virginia opossum, the only species found in the United States and Canada, is often simply referred to as an opossum. These intriguing critters weren't found in Connecticut prior to the early 1900s.
The word "opossum" comes from the Powhatan language, first recorded between 1607 and 1611. In North America, the Virginia opossum is commonly referred to as a possum, sometimes rendered as 'possum. However, true possums are native to Australia and New Guinea and belong to a different order.
Physical Characteristics and Adaptations
The opossum is a medium-sized animal, measuring between 15 and 20 inches long (excluding the tail) and weighing between 4 and 12 pounds. They typically have long, coarse, grayish-white fur, though black, brown, and albino opossums have been found, but are very uncommon. Opossums possess a sharp-pointed and slender muzzle, prominent thin ears, and short legs.
One of their most distinctive features is a long (9-20 inches), scaly, scantily-haired, prehensile tail that helps stabilize the opossum when climbing. The tail is well adapted for grasping and wrapping around things, but not for hanging for long periods. Opossums have five toes on each foot, with the first toe on the hind feet being opposable, clawless, and thumb-like, aiding in grasping branches.
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These physical characteristics make opossums highly adaptable to various environments, allowing them to thrive wherever food, water, and shelter exist. They commonly inhabit woodland areas along streams, ponds, lakes, swamps, and marshes, with farmland and woodlots preferred over extensively forested areas.
Dietary Habits: An Opportunistic Omnivore
Opossums are opportunistic omnivores, meaning they consume both plant and animal matter. Their adaptability to different environments has allowed them to consume a wide array of food sources. They are primarily nocturnal feeders, using their keen sense of smell and touch to find meals.
Common food sources for opossums include:
- Fruits, vegetables, nuts, and seeds
- Insects, small mammals, birds, and eggs
- Carrion (dead animal flesh)
- Garbage and human food scraps
Carrion is a particularly favored food source, providing a readily available source of protein. In residential neighborhoods, opossums forage for vegetables, fruits, garbage, bird seed, and pet food. Fresh meat and roadkill are also dietary staples. The opossum diet changes slightly depending on the season. Opossums depend on smell and touch to find meals.
Opossums as Scavengers: Nature's Cleanup Crew
Opossums are known for their scavenging habits, making them excellent at cleaning up scraps and leftovers. They play a unique role in ecosystems by consuming a wide range of food, including fruits, insects, small vertebrates, and carrion. This scavenging behavior helps prevent the spread of disease and contributes to a cleaner environment.
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Benefits of Opossums in Your Yard
Having opossums in your yard can provide several benefits. Apart from their pest control abilities, opossums help manage tick populations, reducing the risk of tick-borne illnesses. They consume insects, rodents, cockroaches, and ticks, acting as natural pest controllers.
Potential Conflicts and Prevention
While opossums offer numerous benefits, their scavenging nature can sometimes lead to conflicts with humans. They may raid garbage cans or steal pet food left outside. Gardens can also be a source of attraction for opossums, as they feed on vegetables, apples, and strawberries.
To prevent opossum damage in gardens, several steps can be taken. Installing a sturdy fence around your garden can be an effective deterrent, as opossums are not skilled climbers. Ensure the fence extends underground to prevent it from burrowing underneath.
Other preventative measures include:
- Eliminating or securing food attractants
- Bringing pet food in at night
- Keeping garbage covered and in a secure area (garage, shed)
- Picking up fallen fruit from under fruit trees
- Protecting gardens with fencing
- Keeping your yard well lit at night
- Eliminating hiding places by putting fencing around structures like decks and sheds
Nutritional Needs and Dietary Recommendations
Achieving good nutrition in opossums is a challenging task. Opossums are not forgiving of a poor diet and can develop health issues like Metabolic Bone Disease (MBD) if fed inappropriately. It's crucial to avoid diets based on canned cat or dog food, chicken or other meats, eggs, kitten chow, dog chow, or excessive amounts of applesauce and human baby cereals.
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The National Opossum Society recommends a diet based on studies of wild opossum stomach contents. This includes a balanced mix of cat chow, vegetables, and yogurt. The diet should be carefully monitored to avoid excessive amounts of naturally sourced Vitamins A or D, or supplementation with pure forms of Vitamins A, D, or CALCIUM in the absence of known deficiency.
Opossums in Urban Settings
Opossums are highly adaptable and resilient in urban settings. Their ability to climb, swim, and live in diverse environments allows them to navigate cities, finding suitable habitats in parks, gardens, and attics. They take advantage of the abundant food sources in urban areas.
When an opossum is living in your attic, under your deck, or in your shed, it is not advisable to try getting rid of opossums on your own. An opossum can become aggressive if cornered and can bite and scratch. It’s imperative to handle opossum infestations immediately. While searching for food, the pests disturb household pets, destroy gardens, transmit diseases, and create nests inside attics, walls, and basements.
Reproduction and Development
In Connecticut, opossums usually begin breeding in early March. The gestation period lasts about 13 days, and opossums produce one to two litters each year. The average litter size is 9, and the young are very tiny (about the size of a navy bean) and blind when first born. They crawl a few inches to the female's pouch, attach themselves to a teat, and remain "locked" on to it for approximately 60 days. After 80 days, young opossums are weaned, leave the pouch, and typically can be seen riding around on the female's back. By 100 days of age, they are usually independent. The next litter is born about two weeks after the first litter is weaned.
As marsupials, female opossums have a reproductive system that includes a bifurcated vagina and a divided uterus; many have a pouch. The average estrous cycle of the Virginia opossum is about 28 days. Opossums do possess a placenta, but it is short-lived, simple in structure, and not fully functional. They give birth to litters of up to 20 young. Baby opossums, like their Australian cousins, are called joeys. The young are weaned between 70 and 125 days, when they detach from the teat and leave the pouch.
Behavior and Defense Mechanisms
Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. They do not dig or put much effort into building their own burrows, but will temporarily occupy abandoned ones. As nocturnal animals, they favor dark, secure areas.
When threatened or harmed, they will "play possum", mimicking the appearance and smell of a sick or dead animal. This physiological response is involuntary, rather than a conscious act. When an opossum is "playing possum", the animal's lips are drawn back, the teeth are bared, saliva foams around the mouth, the eyes close or half-close, and a foul-smelling fluid is secreted from the anal glands. The stiff, curled form can be prodded, turned over, and even carried away without reaction.
Threatened opossums (especially males) will growl deeply, raising their pitch as the threat becomes more urgent. Males make a clicking "smack" noise out of the side of their mouths as they wander in search of a mate, and females will sometimes repeat the sound in return. When separated or distressed, baby opossums will make a sneezing noise to signal their mother. The mother in return makes a clicking sound and waits for the baby to find her.
Health and Safety Considerations
While any mammal can be infected with rabies, rabies is exceedingly rare in opossums. Their lower blood temperature of 94-97 degrees Fahrenheit might contribute to this.
Horse owners should pay attention to the risk of opossums transmitting Equine Protozoal Myeloencephalitis (EPM) through fecal contamination of feed and water. The disease is caused by a protozoal parasite whose eggs are shed in an opossum’s feces.
Conservation Status and Management
The opossum can legally be trapped and hunted in Connecticut. Having an opossum in your yard shouldn't be a problem. This non-aggressive and nondestructive animal will not dig up yards, attack or threaten pets, or dig burrows.