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Virginia opossum

life science Maturity 9-11 Next article →

The Virginia opossum, scientifically known as *Didelphis virginiana*, is a unique mammal. It is a marsupial, which means it belongs to a group that carries its young in a pouch.

Didelphis virginiana with young
Didelphis virginiana with young

This species is the northernmost marsupial on Earth. Its range stretches from southern Canada down to northern Costa Rica. Many people simply call it a "possum." However, this is different from the animals found in Australia. The name "opossum" actually comes from the Algonquian word for "white animal."

Opossums have several specialized physical features. They possess long, hairless, prehensile tails. A prehensile tail is one that can grasp or hold things, like a fifth limb. They also have opposable, clawless thumbs on their rear limbs.

Virginia opossum opposable thumb
Virginia opossum opposable thumb

This allows them to grip branches or objects effectively. Their mouths are quite impressive and contain 50 teeth. This is more teeth than any other land mammal in North America.

Opossum Skull
Opossum Skull

Despite these features, their brains are relatively small. An opossum's brain is only about one-fifth the size of a raccoon's brain.

These animals are highly successful opportunists. They are omnivores, meaning they eat both plants and animals. Their diet includes insects like beetles and grasshoppers. They also eat small animals, such as mice, rats, and frogs. In the autumn, they favor plant foods like berries, acorns, and persimmons.

Many opossums live near humans in settled areas. They often scavenge from trash cans, compost piles, and pet food dishes. While some believe they eat thousands of ticks, a 2021 study of wild opossums in Illinois did not find ticks in their stomachs.

Opossums have a fascinating history of movement. Their ancestors evolved in South America. They moved into North America during the Great American Interchange. This happened after the Isthmus of Panama formed about 3 million years ago. The *Didelphis* genus arrived in North America about 0.8 million years ago. Since then, their range has expanded significantly. Originally, they lived as far north as Maryland. Now, they inhabit much of New England, New York, and southern Ontario. This expansion was helped by the clearing of forests and the loss of their main predators.

There are several reasons why the opossum's range is growing. Some scientists believe global warming causes warmer winters, allowing them to move north. Others suggest they may have traveled on motor vehicles or trains. They were also intentionally introduced to the West Coast during the Great Depression. They are not well-adapted to heavy snow or very cold winters. If a particularly harsh winter occurs, their northern populations may decrease. They are most active during the spring and summer months. They do not hibernate, but they stay in dens when temperatures drop below freezing.

When an opossum feels threatened, it uses clever defense mechanisms. First, it may try to look intimidating. It can bare its 50 teeth, hiss, and stand its fur on end. If this fails, it will "play possum."

PlayingPossum
PlayingPossum

This is a state of feigned death used to deceive predators. The animal lies limp and motionless with its mouth and eyes open. Its heart rate drops by half during this process. Its breathing becomes so shallow it is hard to detect. This state can last for several hours until the threat leaves. They can also release a smelly fluid to repel predators.

Understanding opossum movement requires looking at their tracks. They use a pacing gait to move. This means they move both limbs on one side of the body at the same time.

American opossum in baby grand piano
American opossum in baby grand piano

Their hind tracks are very distinctive because of their opposable thumbs. The thumb often prints at a 90-degree angle to the other toes. An adult's stride is usually between 7 and 10 inches. By studying these patterns, researchers can identify the animal even if the tracks are faint.

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🖼️ Images & Media (7)
File:Opossum Skull.jpg
Opossum Skull.jpg
File:Virginia opossum opposable thumb.jpg
Virginia opossum opposable thumb.jpg
File:PlayingPossum.jpg
PlayingPossum.jpg
Possum rejects bagel.webm
File:Possum122708.JPG
Possum122708.JPG
File:Didelphis virginiana with young.JPG
Didelphis virginiana with young.JPG
File:American opossum in baby grand piano.jpg
American opossum in baby grand piano.jpg
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