Information about Opossums

information about opossums didelphimorphia

The opossums, also known as possums, are marsupial mammals of the order Didelphimorphia. This is the largest order of marsupials in the Western Hemisphere, as it comprises 103 or more species in 19 genera. The opossums have an unspecialised biology, flexible diet, and reproductive habits that make them successful colonisers and survivors in diverse locations and conditions. Despite its appearance, the opossum is not related to the rat. In fact, as the opossum is a marsupial, or “pouched” mammal, is therefore related to other marsupials such as the kangaroo and the koala. Like kangaroos and koalas, infant opossums stay inside the mother’s pouch to nurse and develop. The opossum holds the distinction of being North Americas’ only marsupial.

information about opossums didelphimorphia

Description and distribution of the opossums

The opossums are small to medium-sized marsupials, ranging in size from a small mouse to a large house cat. They have a remarkably robust immune system, and show partial or total immunity to the venom of rattlesnakes, cottonmouths, and other pit vipers. Opossums are about eight times less likely to carry rabies than wild dogs, and about one in eight hundred opossums is infected with this virus.
They measure 13–37 in (35–94 cm) long from their snout to the base of the tail, with the tail adding another 8.5–19 in (21.6–47 cm). Weight for male individuals ranges from 1.7 to 14 lb (0.8–6.4 kg) and for females from 11 ounces to 8.2 lb (0.3–3.7 kg). They are one of the world’s most variably sized mammals, since a large male from northern North America weighs about 20 times as much as a small female from the tropics. Their fur is greyish brown and have long hairless tails which can be used to grab branches and carry small objects. Opossums also have 50 teeth, more than any other North American land mammal, and opposable, clawless thumbs on their rear limbs.
They are not territorial in the strict sense of the term, but the opossum does represent a solitary specie that excludes other individuals from its area when these are encountered. An opossum’s territory is highly variable and depends on the availability of food and on the individual opossum’s tendency to wander. They generally have elongated rather than circular territories, as they follow the edges of streams or rivers. If food is plentiful, then the range of their territory can be very small, but if food is scarce, the opossum can travel up to two miles in search for food.

Breeding and dietary information

As a marsupial, the opossum has a reproductive system including a divided uterus and marsupium, which is the pouch. Once born, the offspring must find their way into the marsupium to hold on to and nurse from a teat. Female opossums may give birth to as many as 20 babies in a litter, but fewer than half of them survive. Some never even make it as far as the pouch. Most of the younglings fail to attach to a teat, although as many as thirteen can attach. The offsprings are weaned between 70 and 125 days, when they detach from the teat and leave the pouch. The opossum lifespan is unusually short for a mammal of its size, usually only two to four years.
Opossums are scavengers, and they often visit human homes or settlements to raid garbage cans, dumpsters, and other containers. They are attracted to the decaying flesh of dead animals and can often be spotted near road kill. Whether rural, residential or in the wilderness, opossums can be a benefit to any area they inhabit. Their diet includes all types of bugs and insects including cockroaches, crickets and beetles, snails, mice and rats. The nocturnal opossum can be attracted to a neighbourhood due to the availability of water, pet food left out at night and overripe, rotting fruit that has fallen from trees. The opossum in turn helps keep the neighbourhoods clean and free of unwanted, harmful garden pests and rodents, which may carry diseases. However, in case of lacking other food sources, they can also attack and eat chickens.

Behaviour and life span

Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. Some families will group together in ready-made burrows or even under houses. Though they will temporarily occupy abandoned burrows, they do not dig or put much effort into building their own. As nocturnal animals, they favor dark, secure areas which can be below ground or above. Although opossums are solitary animals, females hang around to help their young. Individuals will defend the space they occupied against other opossums at given times.
Although the opossums have a high mortality rate at all stages in life, this is particularly high in its first year of life. Of the younglings that survive until after weaning to go out on their own, fewer than ten percent survive in the first year. Thus the turnover rate of the opossum population is rapid and the indigenous population of a certain region is heavily weighed towards the young. Their most often causes of death are due to automobiles, hunting and trapping, diseases and parasites, exposure and starvation. Although predators such as owls, foxes, coyotes and domestic animals such as cats and dogs can reduce the numbers of young opossums, they do not cause a significant effect in the adult population.

These animals are also most famous for “playing possum.” When threatened by dogs, foxes, or bobcats, opossums sometimes flop onto their sides and lie on the ground with their eyes closed or staring fixedly into space. They extend their tongues and generally appear to be dead. This ploy may put a predator off its guard and allow the opossum an opportunity to make its escape. Opossums are excellent tree climbers and spend much of their time aloft, as they nest in tree holes or in dens made by other animals. They are aided in this by sharp claws, which dig into bark, and by their long gripping tail, that can be used as an extra limb. However, Opossums are very slow animals which causes many of them to be killed by automobiles, as many as 9 million a year.

Opossums as pests

Health related, opossums are dangerous animals as they carry diseases such as leptospirosis, tuberculosis, relapsing fever, tularemia, spotted fever, toxoplasmosis, coccidiosis, trichomoniasis, and Chagas disease. They may also be infested with fleas, ticks, mites, and lice, and are hosts for cat and dog fleas, especially in urban environments.
They are considered pests due to their habits of scavenging and living in attics and under houses. Their most common behaviour as pests includes the following:

  • Opossums living in the attic
  • Opossums living under deck or house
  • Dead opossum on property or roadside
  • Stealing pet food or bird seed
  • Sick, potentially dangerous opossum
  • Presence is alarming dogs/pets

Because they are opportunistic scavengers, they will steal garbage or pet food. They can distress pets, spread fleas and other parasites, and most of all, they often like to live in human structures, such as under sheds or decks, or even attics. They can leave droppings everywhere, cause destruction in houses, sheds and attics. In addition to this, opossums very frequently die inside buildings walls, causing a horrible smell and making it hard to reach their carcass.
Take into consideration the fact that opossums are very common in urban areas, more common, in fact, than in wild ones. They are often nomadic, so sometimes they’ll just wander about from place to place. But they do oftentimes choose to live in one place for a long time, and they especially seem to like man-made structures. They seem to really like living in the walls of homes, and they often live under houses, where they can climb up the walls or through the hole under the bathtub outlet.

This is why finding ways of preventing opossums from taking over your house or yard is important.  Such preventive measures can be trimming branches on trees around your home, protecting any vents in your home, keeping a clean environment around the house and a proper deck design that does not aid the pests in entering the structure of the house. These and other preventive measures are shown in detail in our article about how to prevent infestation with opossums in and around your house.

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