Virginia Opossum

The Virginia opossum is the world’s northernmost marsupial, and the only opossum found north of Mexico. It is also called the North American opossum. Locals often call it possum, ‘possum, or opossum in Canada and the United States. Mexicans call it tlacuache, tacuachi, and tlacuachi, which come from the Nahuatl word tlacuatzin.

This mammal is one of the most primitive animals, having relatively changed little for over 50 million years.

Description

Length: 13–22 inches (33–55 cm), on average, from the snout to the base of their tails.

Female:  16.0 inches (40.6 cm) Male: 16.1 inches (40.8 cm)

Tail: Female:  11.1 inches (28.1 cm) Male: 11.6 inches (29.4 cm)

Weight: Female:  4.2–4.6 lb (1.9–2.1 kg) Male: 4.6–6.2 lb (2.1–2.8 kg)

Body and Coloration:  Their body is covered with dull brownish-gray fur, except for their white faces. They do not have hair on their ears, noses, and tails. The heads of these possums are cone-shaped with black, beady eyes and long flat noses. There are five toes on each of their limbs with opposable thumbs. Each of their toes has claws except the opposable thumbs on their rear limbs. These animals have a total of 13 mammae, which are arranged in a circular pattern with one in the middle.

Opossums have a total of 50 teeth. Among all North American mammals, the Virginia opossum has the most incisors. For example, while other mammals have up to 6 upper incisors, opossums have 10.

Range and Distribution

Their range extends to Central America, including Belize, Costa Rica, El Salvador, Mexico, Guatemala, Honduras, and Nicaragua. These animals also occur from British Columbia’s west coast, Canada to Baja California.

After 1900, their range expanded across the US, in Michigan, Minnesota, New England, Maine, New York, Nebraska, southeastern South Dakota, and Wisconsin. They also occur in the southern and eastern parts of Ontario, and southwestern Quebec in Canada.

Habitat

Opossums live in a variety of habitats with a preference for wet areas. They inhabit deciduous forests, farmlands, marshes, mangroves, mixed forests, open woods, swamps, streams, temperate broadleaf, temperate coniferous forest, tropical dry forest, and tropical moist forests.

These mammals can be seen in human settlements dwelling around compost piles, gardens, trash cans, etc.

Diet

Opossums are omnivores, feeding on a wide range of plants and animals.

They mainly consume amphibians, birds, crayfish, carrion, eggs, frogs, fish lizards, meadow voles, mice, rats, young rabbits, and even snakes due to resistance towards their venom.

In late summer, fall, and early winter, they prefer apples, acorns, beechnuts, blackberries, raspberries, vegetables, and persimmons, specifically in autumn.

These possums also display insectivorous behavior, mainly feeding on beetles, crickets, grasshoppers, and ticks, devouring 95% of all the ticks they run into, approximately 5,000 per season.

In urban areas, they might scavenge from bird feeders, compost piles, unattended pet food, garbage cans, and vegetable gardens.

Behavior

• If threatened, opossums tend to fake death by lying on their side. They remain motionless, keeping their eyes and mouth open, tongues hanging out, and feet clenched. This behavior lasts for several hours or at least until the threat backs away.
• Normally in defense, they react by taking a stand, baring their teeth, hissing, and drooling. They snap their jaws, and to look bigger, they stand their fur on end. But, they mostly prefer to flee.
• During spring and summer, this species is most active. Even though they do not hibernate in winter, they display low activity. In regions below 19 and 25 °F, they may stay in their dens for several days.
• Primarily nocturnal, opossums can still forage during the day around human settlements where the predatorial threat is low.
• Females carrying young forage in the evening and late at night.

Lifespan

These mammals live for two years in the wild and four years in captivity.

Adaptations

• When afraid, they release a green fluid with a putrid odor from their anus, which helps to repel threats. This makes them appear unappetizing, and predators may leave them alone.
• These mammals can drop their pulse rate by half and slow their breathing while playing dead to make it more believable for predators.
• Their prehensile tails help them in carrying small objects and grabbing onto branches.

Mating and Reproduction

The breeding season varies depending on location. For instance, it ranges between January and August at 30° N latitude but starts from February to September at 44° North latitude. Opossums are polygynous, i.e., males have multiple female partners.

During this season, males compete with each other for females by staining their fur with musky odor using a scent gland on their chest that only they possess. The estrous cycle in females lasts for approximately 29.5 days; during this cycle, breeding starts immediately. After breeding, females become aggressive and solitary.

In cool regions, these mammals give birth to a single litter yearly, but in their warmer ranges, the number of litters can be up to three. After 12-13 days of gestation, females give birth to 4-25 altricial young, weighing about 0.13 to 0.20 grams and measuring 14 mm long. These offspring latch on to their mother’s mammae for at least 50-70 days. Around 85 days, they start consuming solid food and are fully weaned between 93-105 days. Once they become fully independent, only about 60% of them survive.

Male Virginia opossums become sexually mature around six months old, and females around eight months old. These mammals usually start breeding at ten months.

Predators

The natural predators of this species include bobcats, coyotes, dogs, foxes, great horned owls, large hawks, and snakes.

Conservation Status

In the Red List of Threatened Species by the IUCN, the Virginia Opossum is “Least Concern” or “LC”.

Many vehicular encounters result in the death of these animals when they “play possum” on the road and sometimes while foraging at night.

Interesting Facts

• Among any marsupials, the Virginia opossums have one of the lowest encephalization quotients, and the size of its brain is one-fifth of that of a raccoon.
• In the American Southeast, Virginia opossums appeared in many folklore tales and were a very popular game animal.
• Heidi, a cross-eyed Virginia opossum from Germany’s Leipzig Zoo, appeared on TV in a talk show to predict the winners of the 2011 Oscars.
• There was a misconception about Virginia opossums giving birth through their noses. This idea came about since they have been seen licking their offspring inside the pouch.